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September 18, 2014 / Nat Anacostia

Nats’ post-season roster: The starting rotation

The Nats are in the enviable position of having five good starting pitchers. With extra days off during post-season play, a four-man rotation can pitch with the usual four days of rest between starts, which means that the worst starter gets bumped out of the rotation. Who’s the Nationals’ odd man out?

If we just ranked them by this season’s ERA, it looks like Doug Fister is the ace:

  1. Doug Fister, 2.55
  2. Jordan Zimmermann, 2.83
  3. Tanner Roark, 2.85
  4. Stephen Strasburg, 3.34
  5. Gio Gonzalez, 3.79

Of course, these decisions shouldn’t be based just on this season’s ERA.

The difference between the stats junkies in the media (I’m looking at you, Thomas Boswell) and the sabermetric researchers is that the media “experts” focus on ever narrower statistics—for example, ERA since the All-Star break, ERA against likely opponents, whereas the sabermetric experts look at a wider set of statistics—multiple years of data, and additional statistics like fielding-independent pitching (FIP) and its relatives (xFIP, SIERA, etc.) I remember Bill James making the point in his Abstracts 30 years ago that you can better predict post-season performance from the players’ statistics for the last two years than from the current season alone. And since then, Voros McCracken taught us that fielding-independent statistics do better at predicting future ERA than does a player’s past ERA.

These factors suggest that the ranking of the Nats’ starters should have Strasburg (3.10 FIP and 2.84 xFIP over 2013–14) and Zimmermann (3.09 FIP and 3.32 xFIP over the same span) on top. Even though Fister’s fielding-independent numbers aren’t as good, with his experience and success at inducing weak contact makes him a natural for the third spot. So the fourth spot comes down to Gonzalez versus Roark.

Gio’s experience and ability to get strikeouts gives him the edge. But I’d also consider the opponent – if the opposing team in a series has hit lefties especially well, I’d be inclined to pick Tanner for that series. Let’s look at the probable playoff teams, 4 teams seem to hit better against lefties than righties:

  • Angels (.276/.340/.436 vs LHP) (.257/.321/.402 vs RHP)
  • Tigers (.284/.339/.453 vs LHP) (.274/.329/.420 vs RHP)
  • Cardinals (.253/.327/.387 vs LHP) (.255/.321/.367 vs RHP)
  • Royals (.264/.322/.381 vs LHP) (.259/.307/.371 vs RHP)

The Dodgers, Athletics, Pirates, and Mariners, on the other hand, hit better against right handers, and the Giants and Orioles are pretty much neutral. So I’d consider putting Roark in the rotation should the Nats face the Cardinals, Angels, Tigers, or Royals.

Who should be the Nationals’ ace—the pitcher called on to pitch the most games and to face Kershaw or Wainwright? In my mind, it’s obvious that it should be Strasburg. Even though his average pitching performance may have been a little worse than the other pitchers in our rotation this season, he’s still the guy who gives you the best chance of pitching that shutdown game that you’d like when you’re up against a Kershaw. For example, in 12 of Strasburg’s 32 starts, he’s had a game score of 65 or higher. None of the Nats’ other starters have more than 9 starts with a game score that high.  Strasburg’s ability to get strikeouts and avoid walks simply gives him the best chance for an outstanding performance, even if he does occasionally get blown out.

The other thing to emphasize is that whoever gets sent to the bullpen (probably Roark) has the chance to play a key role in saving games in long relief, as Lincecum demonstrated in the Giant’s 2012 World championship post-season. If a starter gets in trouble early, he’d give us the chance to still come back and win the game.

September 16, 2014 / Nat Anacostia

Congratulations NL East champions!

The Nats clinched the division, beating Atlanta the same way they’ve been winning all year—behind excellent starting pitching (in this game, Tanner Roark), just enough offense (thank you, Ian Desmond, for tonight’s offense), and a pretty good bullpen (nods to Tyler Clippard and Drew Storen).

It’s been a wonderful season. I’ll be back later this week with thoughts on preparing for the post season.


September 7, 2014 / Nat Anacostia

Nats’ post-season bullpen: How does it compare?

Post-season baseball is different from regular season baseball, and nowhere are the differences more apparent than in the bullpen.

With more rest days and the season on the line, the concerns about saving the bullpen are greatly diminished. More innings, as a share of total innings, go to the back of the bullpen. If the team has an ace reliever, he can make a tremendous difference in the post-season, as the Yankees demonstrated repeatedly with Mariano Rivera, and as the Red Sox demonstrated last year with Koji Uehara. The other relievers in the pen are used in more situational roles. The fifth starter generally moves to the bullpen as the long man and, as the Giants demonstrated in 2012 with Tim Lincecum, he can help win games. Other starters are sometimes called on to pitch in relief, especially when a series is on the line.

With the recent demotion of Rafael Soriano from the closer role and general concerns about the performance of the Nationals’ bullpen, I decided to compare them with the pitchers who are likely to constitute the back of the bullpen for the other 12 teams that are still in the running for the post season.

Of course, measuring relief pitcher talent is difficult, starting with the fact that relief pitchers generally face only 250 to 300 batters per season. Consequently, performance can usually be better assessed using data for more than one season. I decided to use a dataset of two-year performance for 216 pitchers who have pitched at least 50 innings (total) in relief during 2013–2014. I focus on 3 statistics:

  • WHIP (walks plus hits per innings pitched) is a measure of how many opposing batters are allowed to reach base per inning pitched—a measure that is very similar to opponents’ on-base percentage. Of course, there is more to pitching than avoiding base runners (such as situational pitching and avoiding home runs), but keeping opposing base runners from reaching base is a very basic way for a pitcher to accomplish his goal.
  • FIP– (fielding independent pitching, relative to league and adjusted for ballpark). This measure ignores hits allowed, which is affected by the defense playing behind the pitcher, and focuses on the three outcomes that the pitcher has most direct control over—strikeouts, walks, and home runs. Like WHIP, it does not take account of situational performance.
  • RE24 – This is a measure of run prevention that is similar to, but in my opinion, superior to ERA. A big problem with ERA for relievers is that it ignores inherited runners. RE24, on the other hand, takes account of the effect of every event on run scoring. It’s a situational measure, so if a pitcher is really good at shutting down the opposition with runners in scoring position, it will be reflected in this measure (even if the runners in scoring position were inherited from a previous pitcher). Unlike ERA, RE24 doesn’t make any attempt to adjust for fielding, so sometimes runs will be charged to a pitcher that are really the fault of the fielders. Of course, ERA’s adjustment for defense is also quite flawed, so if you want a measure that is truly independent of fielding, FIP– is a much better option.

For the Nationals, I’ll show data for their 8 main relief pitchers. For each of the other potential playoff teams, I’ve tried to select the 3 pitchers that are most likely to constitute the back of their bullpen, based on data on how well they’ve been pitching and how they’ve been used (such as saves and holds). Of course, I don’t follow all of these teams closely, so I probably made poor choices in a few cases. If so, you are welcome to look up the numbers for whoever you think fits better.

For each statistics, I’ll give the value of the statistic for the player (over the 2-year period, 2013–14) and in parentheses, the rank among the 216 relief pitchers in my dataset. One way to think about the ranks is that if the pitchers were randomly distributed among the 30 teams, the best pitcher on each team would probably be ranked somewhere 1 to 30, the second best 31 to 60, the third best 61 to 90, and so forth. So for an “average” team, you’d expect the top 3 relievers to rank between 1 and 90. Of course, the various measures result in different rankings, which is the point of presenting all of them.

Rafael Soriano 1.19 (90) 91 (115) 11.12 (67)
Tyler Clippard 0.93 (11) 89 (102) 18.63 (32)
Drew Storen 1.22 (107) 90 (107) 4.28 (121)
Craig Stammen 1.26 (128) 78 (45) 6.77 (106)
Matt Thornton 1.28 (140) 83 (72) –1.05 (167)
Jerry Blevins 1.16 (76) 92 (117) 1.29 (149)
Ross Detwiler 1.40 (182) 113 (197) -3.78 (184)
Aaron Barrett 1.37 (172*) 71 (27*) -1.62 (173*)

* Aaron Barrett has less than 50 innings pitched, so he wasn’t included in the ranking. The ranks shown are where he would have ranked had he pitched more than 50 innings.

The striking thing about the Nationals’ bullpen is how almost everyone is average or a little better than average. The exceptions are Tyler Clippard, who is better than average, at least in keeping runners off base and preventing runs, and Ross Detwiler, who has been below average. They’ve been able to put up respectable relief pitching numbers during the season despite lacking the top-end talent because they don’t have the big drop-off that comes with the below-average pitchers who also appear in most teams’ bullpens.

For Clippard, one of his weaknesses is that, as a fly-ball pitcher, he sometimes gives up home runs. That’s reflected in his worse ranking for FIP– (which takes account of home runs allowed) than for WHIP (which doesn’t). The interesting thing is that his runs allowed (RE24) rank quite a bit better than his FIP–, which I attribute to one of his abilities that isn’t measured in FIP. Batters facing Clippard have always hit an unusually high number of infield flies (pop ups), which of course almost always result in outs. The ability to induce infield flies can be very valuable, especially for pitchers who are very good at it.

But Soriano shows up as just a slightly better than average pitcher, not a relief ace. As we’ll see, there are a few other teams who also have overrated closers (such as the Giants, Tigers, and Mariners), but the dissatisfaction with Soriano is obvious. In fact, that’s why I was hoping before the trade deadline that Mike Rizzo would deal for a top reliever, someone like Papelbon or Cotts. Matt Thornton was an ok addition, but not really comparable to the back-of-the-pen guys on some our prospective opponents.

For comparison, here are the top guys from the other teams that still have post-season hopes:


Craig Kimbrel 0.90 (8) 49 (5) 27.95 (7)
David Carpenter 1.11 (49) 74 (31) 13.84 (49)
Jordan Walden 1.14 (58) 74 (32) 10.45 (73)



Trevor Rosenthal 1.24 (120) 66 (20) 15.58 (45)
Seth Maness 1.19 (88) 93 (120) 17.71 (36)
Pat Neshek 0.95 (14) 88 (97) 19.97 (28)



Francisco Rodriguez 1.08 (40) 102 (166) 16.80 (42)
Jonathan Broxton 1.11 (48) 102 (167) 10.63 (70)
Will Smith 1.25 (124) 85 (83) 4.35 (119)



Mark Melancon 0.93 (12) 52 (7) 22.69 (14)
Tony Watson 0.95 (16) 84 (79) 24.54 (11)
Justin Wilson 1.17 (79) 93 (121) 14.18 (47)



Kenly Jansen 0.99 (24) 55 (9) 20.61 (25)
Paco Rodriguez 0.96 (17) 80 (53) 11.95 (62)
JP Howell 1.05 (34) 80 (56) 36.33 (1)



Sergio Romo 1.04 (32) 100 (157) 4.13 (123)
Santiago Casilla 1.11 (47) 97 (140) 27.21 (8)
Yusmeiro Petit 0.88 (6) 51 (6) 13.60 (50)



Zach Britton 0.89 (7) 77 (43) 21.24 (20)
Darren O’Day 0.95 (15) 83 (76) 30.26 (5)
Andrew Miller 1.05 (37) 52 (8) 21.49 (19)



Greg Holland 0.92 (9) 42 (2) 34.60 (2)
Wade Davis 0.80 (2) 40 (1) 29.23 (6)
Kelvin Herrera 1.15 (63) 81 (64) 20.99 (21)



Joe Nathan 1.18 (84) 75 (38) 11.81 (64)
Joakim Soria 1.19 (93) 66 (19) 2.18 (141)
Joba Chamberlain 1.48 (198) 107 (179) –5.93 (192)



Huston Street 0.98 (22) 107 (182) 18.91 (30)
Joe Smith 1.01 (27) 85 (84) 23.90 (12)
Jason Grilli 1.16 (74) 73 (29) 6.77 (107)



Sean Doolittle 0.84 (5) 57 (11) 26.73 (9)
Luke Gregerson 1.00 (25) 81 (62) 9.58 (79)
Ryan Cook 1.19 (97) 79 (51) 4.76 (115)



Fernando Rodney 1.31 (151) 71 (27) 8.13 (92)
Charlie Furbush 1.18 (86) 80 (58) 5.02 (112)
Danny Farquhar 1.14 (60) 60 (13) 13.15 (52)


I guess I come away from this comparison deeply discouraged. The Royals and Braves sure have great bullpens. And while the Nats have a decent enough bullpen overall, compared to many of these other teams, the back of the Nats’ bullpen shows up as mediocore. Quite a few of the contending teams have at least one reliever who has a demonstrated ability to really shut down the opposition, whereas for the Nats, only Clippard really aspires to be that guy, and with his weakness for home runs, he doesn’t really that bill either. While it’s not impossible to win with a mediocore back of the bullpen, it’s definitely one of the team’s weaknesses—perhaps their most important one.

September 4, 2014 / Nat Anacostia

Comments on yesterday’s 14-inning marathon

Here are a few random thoughts on yesterday’s 14 inning, 8–5 victory over the Dodgers:

  • I was only able to watch the last couple of innings, heard a couple more innings on the radio, and followed some of the play by play on my phone. When I first heard about Jayson Werth dropping the fly ball in the bottom of the 9th to tie the game, my first thought was “why wasn’t Michael Taylor playing right field as a defensive substitute?” One reason, of course, is that Mike Rizzo hadn’t called up Taylor—I just sort of assumed that he had. But if I were managing the Nationals, in September I’d want to have a defensive substitute in there for Werth anytime the Nats had a lead in the 9th inning. Werth isn’t an awful fielder (and when I finally saw the replay, it was clear that the sun, and not Werth’s fielding ability, was mostly responsible for the missed catch), but still Werth now has below average range and has a lot of aches and pains, so I’d want to use a defensive substitute pretty regularly in September. If not Taylor, then Eury Perez or Jeff Kobernus or someone with better range.
  • In the top of the 11th, I thought it was really weird that Matt Williams asked Asdrubal Cabrera to sacrifice after Adam LaRoche led off the inning with a hit by pitch. I mean, Cabrera is clearly a much better hitter than the two guys following him—Sandy Leon and Kevin Frandsen, so why not take your best chance letting Cabrera swing away?
  • I was surprised that Jerry Blevins was called on to pitch a full inning in the bottom of the 11th, but after tracking through the play by play, I see how Matt Williams got to the point that he had to use him. If he had know that the game would go 14 innings, it obviously would have made more sense to use Blevins to get the last two outs in the 7th and ask Matt Thornton to pitch the 11th, but of course Williams couldn’t have known that. Fortunately, Blevins’ LOOGY skills enabled him to get the final two outs, but that was a tough inning. I’d hope that for the rest of this year Blevins would rarely be called upon to face right handers in high leverage situations.
  • Although the run that Rafael Soriano gave up in his blown save was unearned, he did walk Ethier to put on the tying run. Rizzo missed his chance to significantly upgrade the bullpen at the trade deadline, and I have a growing sense of dread about the Nats’ bullpen and the post season.
  • A few years ago, someone did an article using some type of sabermetric measure to identify the most exciting games played during the season. I don’t really remember the metric, but it may have been something like adding up the absolute value of the win probability added. I’d guess that this game would rank among the top 5 or 10 games of the year using that type of metric. Plus, these were two playoff-bound teams that were treating it as a dry run for a post-season showdown. It was quite a game.



September 1, 2014 / Nat Anacostia

Nats’ August in review: I want another ring

In August the Nationals finally played like the championship-caliber team that we’ve been looking for all season. Entering the month with a 1-1/2 game lead over the Braves in the NL East, the Nats went 19–10 and finished the month with a 6-game lead. The month featured a lot of wild games, including a 10-game winning streak that featured five walk-off wins. The Nats’ success was more than just  winning close games on luck, as demonstrated by their run differential of +40 in August.

The month began with the Nationals at home playing the last three games of a 4-game series against the Phillies (they had lost the first game on July 31). After taking another loss, they won the last two games to split the series. They then lost to the Orioles in a make-up game for an earlier rain-out.

Next, the Mets came to Washington for a 3-game series. After losing the first game to New York, the Nats were in a bit of a slump, having dropped six of their last nine games. Matt Williams kicked up a bit of a media kerfuffle when he responded to a question on a radio talk show about whether slumping Bryce Harper should be sent to  But that night, they beat the Mets 7 to 1, and the following afternoon they finished a 13-inning, 4 hour and 34 minute marathon when Harper launched a walk-off home run into the left-field stands.

The team’s roster also evolved during August. Asdrubal Cabrera, acquired in a deadline deal, played his first game on August 1 and took over the main responsibilities at second base. On August 4, Nate McLouth, who hadn’t reached base in his last 17 plate appearances dating from late June, went to the disabled list for shoulder inflammation (and later to season-ending surgery). At about the same time, the Nats claimed relief pitcher Matt Thornton from the Yankees on waivers. McLouth was first replaced by Steven Souza Jr. until he injured his shoulder, when Michael Taylor was called up. Taylor hit a home run in his debut game. Late in the month, Nate Schierholtz was signed and took over as the Nats’ extra outfielder.

On August 8, a short road trip began with three games in Atlanta. Stephen Strasburg lost the first game, continuing his struggles in Atlanta, but behind Tanner Roark the Nats were able to win the second game, though they lost the finale with Gio Gonzalez on the mound. Next came a 3 game set against the Mets in New York, and the Nats swept the series. The Nats were 4–2 on the road trip.

Returning to Washington, the Nats faced the Pirates and won all three games by one run, with the last two featuring walk-off victories. In a four-game set against the Diamondbacks, the Nats again swept, winning the first game and the last two with walk offs, giving them five walk offs in six games and their first 10-game winning streak since 2005.

The home stand concluded with a three-game set against the Giants. The Giants won the first game, but the Nats won the last two. In the third game, Strasburg was shelled early and the Nats were behind 5–0 after the top of the fourth and 6–2 after the top of the sixth. But beginning in the 6th inning, the Nats scored 12 runs to clobber the Giants 14 to 6. Overall, the Nats were 9–2 on the home stand.

The last six games in August were on the road. The Nats went to Philadelphia and were swept, though two of the losses were decided by a single run. The concluding series was against the Mariners in Seattle. In the opener, they faced “King” Felix Hernandez and belted him for 4 home runs (6 total) in an 8 to 3 victory. They also won the second game, but lost the finale.

The Nats’ offense was working well in August, ranking 4th in the National League in on-base percentage (.327), tied for first in slugging percentage (.435), and led the league in home runs (40). In park-adjusted weighted runs created (wRC+) they ranked 2nd behind the Giants with 112, or 12% better than the average team.

Their starting pitchers led the league in ERA– with 80 (or 20% better than the average team)—this is a measure of ERA that is park-adjusted and measured relative to the league. The Nats were tied for first with the Reds in the version of pitching WAR that is based on runs allowed (RA9-WAR). In the fielding-independent metric, FIP–, the Nats’ starters ranked third with 99. For relievers, my preferred metric is RE24, which takes account of game situations, such as inherited runners. The Nats relievers ranked 5th in the NL with an RE24 of 5.52. Although it may have seemed like there were a lot of meltdowns during August, the relievers actually had the second lowest number of meltdowns in the league, with 9.

The Nats finished the month 6 games ahead of the Braves and well-positioned for an NL East title. The attention of Nats fans is beginning to turn to the post-season.



19-10 (.655)

Pythagorean Record:

19-10 (4.66 R/G – 3.28 RA/G)

Playoff odds at the end of the month:

Baseball Prospectus:  95.9% for Division championship, 99.2% for playoffs

FanGraphs (projection mode): 98.0% for Division, 99.6% for playoffs

FanGraphs (season-to-date mode): 96.6% for Division, 99.4% for playoffs


August MVP:

Jordan Zimmermann (4-0, 2.43 RA/9, 6 G, 40-2/3 IP, 7.7 K/9, .255 opp OBP, 1.3 RA9-WAR).

Most valuable position player:

Anthony Rendon (.287/.344/.496, 29 G, 5 HR, 22 R, 15 RBI, 1.2 fWAR).

Most valuable relief pitcher:

Matt Thornton (1-0, 0.00 RA/9, 10 G, 8 IP, 5.6 K/9, .214 opp OBP, 3.49 RE24, 0.5 RA9-WAR).

Worst month:

Ross Detwiler (1–0, 6.97 RA/9, 8 G,10-1/3 IP, 5.2 K/9, .388 opp OBP,  –5.01 RE24, –0.3 RA9-WAR).


Best start this month:

Stephen Strasburg (August 3, 4–0 win over the Phillies in Washington) pitched 7 scoreless innings, giving up 3 hits and 1 walk while striking out 10, for a game score of 80.

Worst start:

Stephen Strasburg (August 24, 14–6 win over the Giants in Washington) gave up 8 hits, 5 runs, 2 home runs, and 2 walks in 4 innings, while getting 4 K and a game score of 28. Starting in the 6th inning, however, the Nats scored 12 runs to overcome a 6–2 deficit and win the game.

Tough losses:

  • Doug Fister (August 1, 2–1 loss to the Phillies in Washington) gave up 2 runs on 6 hits and 2 walks with 5 strikeouts in 7 innings (game score 60).
  • Tanner Roark (August 25, 3–2 loss to the Phillies in Philadelphia) gave up 2 runs on 5 hits and 1 walk with 2 strikeouts in 6 innings (game score 55).

Cheap win: 

  • Tanner Roark (August 15, 5–4 win over the Pirates in Washington) gave up 3 runs on 5 hits and 2 walks with 4 strikeouts in 5-2/3 innings (game score 49).

Best shutdown:

Craig Stammen (August 7, 5–3 win over the Mets in Washington) entered a game tied 3–3 in the top of the 11th and pitched 3 scoreless innings, giving up 1 hit and 2 walks (Win probability added .383). In the bottom of the 13th, Bryce Harper hit a walk-off homer for the win.

Worst meltdown:

Rafael Soriano (August 17, 6–5 win over the Pirates in Washington). Soriano entered the top of the 9th with a 4–2 lead. Marte led off and Soriano hit him, then gave up a single to Snider. A wild pitch scored Marte and moved Snider to 2nd, and Davis walked. Soriano got the first out when Sanchez hit into a fielder’s choice, but Polanco then doubled to drive in both base runners and giving the Pirates a 5–4 lead (WPA –.798). Matt Thornton got the last two outs in the top of the 9th, and the Nats tied it in the bottom of the inning on an RBI single by Asdrubal Cabrera, before coming back to win it in the 11th on a Scott Hairston sacrifice fly.

Clutch hit:

Wilson Ramos (August 18, 5–4 win over the Diamondbacks in Washington). With 2 outs in the bottom of the 7th, Desmond on first, and the Nats trailing, 1–0, Ramos hit a home run to give the Nats a 2–1 lead (WPA .482). Later in the same game, Anthony Rendon hit a triple to tie the game 3–3 (WPA .397) and Adam LaRoche hit a walk-off solo home run in the 11th (WPA .468). LaRoche hit another notably clutch home run on the 16th against the Pirates, a two-run shot in the bottom 8th to tie the game 3–3 (WPA .407).


Anthony Rendon (August 16, 4–3 win over the Pirates in Washington). Trailing 3–1 in the bottom of the 8th, no outs, Kevin Frandsen on first, and Denard Span on second, Rendon grounded into a potentially rally-killing double play (WPA –.227). Fortunately, Adam LaRoche followed Rendon with the clutch 2-out, 2-run, game-tying home run that was mentioned in the last paragraph, and the Nats won in walk-off fashion in the bottom of the 9th on a Wilson Ramos RBI double.

August 7, 2014 / Nat Anacostia

Tanner Roark’s remarkable first year

Quick – Name the the top five MLB pitchers in earned run average over the last calendar year: 1) Clayton Kershaw, 2) Felix Hernandez, 3) Anibal Sanchez, 4) Jon Lester, and 5) Tanner Roark! In Roark’s first full year as a major league pitcher, he’s pitched 194-2/3 innings and gone 18–8 with a 2.54 ERA.

One year ago today, the then-26-year-old Roark made his MLB debut in a two-inning relief appearance against the Braves, an appearance watched by families and friends in a garage in his hometown of Wilmington, Illinois. At the time, Roark was the third, and least regarded member of a trio of starting pitcher prospects, along with Taylor Jordan and Nate Karns, who served as the Nats’ injury reserve along with Ross Ohlendorf and Yunesky Maya. That first outing, I remember being impressed that he was throwing strikes and seemed to know what he was doing on the mound, but I also remember thinking that major league hitters would figure out how to hit his less than overwhelming stuff.

It’s a year later, and they still haven’t figured it out. How has he done it? First, by throwing strikes—especially strike one. Among 81 qualified pitchers over the last calendar year, Roark ranks 15th lowest in walks per 9 innings, with 1.90. He also ranks among the leaders in two statistics that are generally regarded as having a large component of luck—ranking 5th lowest in batting average on balls in play (BABIP) with .262 (most pitchers regress to something like .290 to .300), and 5th lowest in home runs per fly ball with 6.3% (most pitchers regress to roughly 10%). Consequently, despite the enthusiasm of MLB Network’s Eric Byrnes, who named Roark the Nationals’ ace,  projection systems continue to see Roark as the least talented of the Nats’ five starters. Nevertheless, he is also regarded as one of the most improved pitchers of this season.

Roark has thrown a mix of 64% fastballs, 16% sliders, 11% curve balls, and 9% change-ups, with an average fastball velocity of 91.5 miles per hour. In the last calendar year he ranks 13th in percentage of pitches in the zone with 48.2% (essentially tied with battery-mate Jordan Zimmermann), but Roark’s contact rate of 82.8% is well above average, while his strikeout rate of 6.75 K/9 is also below average.

A number of writers have recently celebrated Roark’s remarkable first season. He has transformed himself from a replacement level bullpen prospect, to a replacement level fifth starter, and now to the best fifth starter in baseball, a pitcher who shows up in the top leader boards. Nationals fans have been fortunate to watch his transformation.

Addenda - Dave Cameron of FanGraphs posted a nice article on Roark’s first year shortly after my piece was posted.

August 5, 2014 / Nat Anacostia

Should Williams have pinch hit for Roark in the 6th?

Based on the results of last night’s game against the Orioles, the answer is obviously no. He also shouldn’t have sent in Craig Stammen to relieve.

But the question I’m asking is a different one—at the time the decision was made, was it good strategy for Matt Williams to allow Tanner Roark to bat with two outs in the bottom of the sixth, a one-run lead, and runners on first and third?

If you read the sabermetric literature, you probably already know the answer. But let’s go through this based on simple reasoning, first addressing some questions that may have been relevant to the decision.

  • Was this a high leverage situation?

Obviously, yes. There’s a “leverage index” available at FanGraphs to track how important the situation is in deciding the outcome of the game. Roark’s at bat in the bottom of the 6th had a leverage index of 1.67, meaning that it was 67% more important than an average plate appearance. Anything above 1.5 is considered to be “high leverage.” Roark’s plate appearance was the third highest in leverage of all of the Nats’ plate appearances that evening. (The higher leverage situations were when Ian Desmond struck out with runners on first and third in the 1st, and when Jayson Werth hit a sacrifice fly in the 3rd to put the Nats ahead 2–1.)

  • How much longer did Williams expect Roark to pitch?

After pitching the top of the 6th, Roark was at 84 pitches, but he had faced 23 batters. Based on past usage patterns, I think the most likely scenario would be that Williams expected Roark to pitch one more inning, before turning the pitching responsibilities over to Tyler Clippard in the 8th and Rafael Soriano in the 9th.

  • Was the bullpen depleted?

After the game, Williams appeared to have based his decision on saving the bullpen, saying “it depends on who else we’ve got available. Bullpen’s been pitching a lot lately…” Looking at the record, however, I don’t see evidence that the bullpen has been especially overused recently. In the prior six days, Clippard had pitched Wednesday, Friday, and Sunday; Soriano had pitched on Friday and Sunday; Jerry Blevins had pitched on Tuesday, Thursday, and Saturday; Blake Treinen had pitched on Saturday; Ross Detwiler and Craig Stammen had pitched on Thursday (with Stammen pitching 2 innings and Detwiler 1-1/3); and Drew Storen had pitched on Wednesday. Maybe Williams was trying to avoid using Clippard, but otherwise the bullpen looked well rested.

  • Is Roark an especially good hitter?

No. In 65 career plate appearances, Roark’s on-base percentage is .161. In comparison, there are 123 active pitchers with at least 60 career plate appearances, among whom Roark ranks 72nd in on-base percentage. As a pitcher, Roark is pretty much an average hitter.

  • Was Roark pitching especially well?

This actually could be a misleading question, because research shows that pitching well early in a game doesn’t necessarily predict how well a pitcher is going to do later in the game. But I’d have to say that no, Roark’s performance was not especially good. He had 3 strikeouts and 1 walk, so he wasn’t missing a lot of bats. It’s true that he had only given up 4 hits to that point, but 2 of those were home runs, and good fielding and saved several other hard hit balls from becoming hits. In my opinion, Roark was a little bit lucky to have only given up 2 runs in 6 innings based on how well the Orioles were hitting him.

  • Should Roark have been expected to pitch better in the 7th than the available reliever?

Batters facing Roark this year have a batting line of .233/.281/.344. In comparison, batters facing Drew Storen have a batting line of .217/.271/.310. So Storen definitely should have been expected to pitch better. But it’s more debatable with some of the other pitchers that were available in the bullpen.  Stammen’s line is .270/.305/.391; Detwiler’s line is .269/.346/.386; Blevins’ line is .232/.302/.331; and Treinen’s line is .278/.333/.347. But the kicker is that Roark (like most pitchers) is much more hittable the third time through the lineup. In their third plate appearance in a game, opposing batters have a line against Roark of .259/.327/.361. Compared with that, almost anyone in the bullpen, with the possible exception of Detwiler, should be expected to have pitched better than Roark in the 7th.

  • How well would a pinch hitter have hit?

That’s hard to say, especially since Nate McLouth went on the DL, and Danny Espinosa and Scott Hairston have been terrible against a right handers. I probably would have gone with newly arrived Steven Souza, though Kevin Frandsen, who’s hit .216/.286/.294 against right handers would also have been a possibility. However, regardless of who had pinch hit, the expected outcome would have been significantly higher probability of a run scoring than with Roark.

So, with no expected improvement in pitching by letting Roark pitch the 7th instead of Storen, and with a definite loss in hitting, there really isn’t a good case for letting Roark hit in that situation. Williams blew it.


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