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.