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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 fit 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.

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