The Royals Bunt to Not Win, Succeed

The main story of the last night’s installment of the Battle for Grass Creek between the Royals and the Mariners was Hisashi Iwakuma. Iwakuma shut down the (admittedly less-than-intimidating) Kansas City bats with an eight-inning effort, during which he allowed only four hits, no walks and no runs, and struck out seven. The Mariners needed all Iwakuma could bring, because the Royals themselves only allowed the Mariners one run. The Mariners’ lone run came right after Royals’ manager Ned Yost made the questionable decision to have left-handed starter Danny Duffy walk the left-handed hitting Robinson Cano to pitch to right-handed Corey Hart. The problems with that decision have been discussed elsewhere. My own short summary: some intentional walks might make sense, but this was not one of them.

Yost made another interesting decision in the bottom of the ninth. With none out, a runner on first and the Mariners’ closer, Fernando Rodney, on the mound, Yost had Norichika Aoki lay down a sacrifice bunt. Aoki did so successfully, but after an Eric Hosmer walk, the Royals made two more outs and it all came to naught. After the game, Yost explained his decision:

Because I want to take a shot at tying it. My ‘pen was strong enough where I felt like I could go ahead and go for the tie. Some nights you don’t. Some nights you play for the win.

Like intentional walks, not all bunts are bad. Sometimes they are the smart play, sometimes they are not. It is not always easy to say one way or the other. Yost’s teams have sometimes bunted in situations where it made sense. Was this one of those situations?

Just about any managerial decision can be subject to analysis from a myriad of angles, and involve many things that cannot be covered in a blog post, even without considering information to which we are not privy — and said information does exist. Of course, this is also true of many things in the world about which we laypeople have opinions, and that does not mean we cannot have and express such opinions. But it must be admitted that we probably do not know everything.

Still, Yost laid out his thinking in a pretty clear manner: he was going for the tie. It is easy and fun to pick on the “Some nights you play for the win” line, but we know what Yost was really trying to say: get the tie in ninth with one run, then give the Royals’ good bullpen a chance to hold the Mariners down while the offense tries to scratch out the win in extras.

Saber-friendly analysts do think there are appropriate times for sacrifice bunts, and in close and late situations one-run strategies are sometimes the right call. This would seem to potentially be one of those situations. Without getting into every angle ourselves, this is a situation in which Win Probability Added (WPA) might help us out. Unfortunately, according to WPA the bunt did not increase the Royals chances of winning, the WPA for the play was -.049.

Now, WPA does not take into account the skills of the individual players involved. It is worth looking more closely to see if it makes a difference. The most relevant player here is Aoki, naturally. Is Aoki a particularly bad hitter, such that he would be better off bunting? Aoki has been on something of a cold streak lately, and (after last night) is hitting just .277/.331/.346 (89 wRC+) on the year. Even if that is poor, his on-base percentage is still above average. More importantly, we know that observed performance is not the same thing as true talent, and for his career Aoki is an above-average hitter (107 wRC+). While ZiPS projects his current true talent as 93 wRC+, Steamer has him as a 110 wRC+ hitter. It is fair to say he is probably about average.

Aoki, a left-handed hitter, also had the platoon advantage versus the right-handed Rodney. Now, some will point out that for career in the North American major leagues, Aoki has a slight reverse platoon split, with a 110 wRC+ versus lefties but a 105 wRC+ versus righties. That is a pretty small split, though, and given the sample sizes of major league plate appearance needed to estimate platoon skill, we are a long way from being able to say that Aoki has enough major league plate apperances versus lefties (he has 430, and at 1000 we regress halfway to league average). As for Rodney, for most of his career he has, as one would expect, fared a bit worse versus left-handed batters. At least on this broad view, platoon consideration do not really help Yost’s case for a sacrifice bunt.

A good case can be made, however, that a bunt might be defensible if it is not just a sacrifice bunt. Aoki might be a decent hitter, but he is clearly no Giancarlo Stanton. Hitting one out was probably not going to happen. What Aoki has shown himself to be good at is bunting for hits. Since he came into the league in 2012, Aoki is third in the majors with bunts for hits with 19. Almost 37 percent of this bunts have gone for hits. Depending on the position of the fielders, bunting for a hit might not be a bad idea.

Aoki’s skill at bunting for a hit is is not relevant to this discussion of tactics, though. Aoki squared up early as if sacrifice bunting, and Yost himself did not suggest that it was anything other than a called sacrifice bunt.

It is impossible to get into every little factor, but a couple more are worth briefly mentioning. Neither make the decision to sacrifice look any better. For one, Aoki is pretty fast, and the numbers suggest that he is less likely to ground into a double play than the average hitter, so that was not a reason to sacrifice (as it might sometimes be).

Finally, it is not as if Rodney looked especially unbeatable. Indeed, before Aoki came to the plate, Rodney walked Alcides Escobar on four pitches. I was not in the Mariners’ dugout, but I would guess there was little talk about not allowing Alcides Escobar to beat them. Rodney’s first pitch to Aoki was a ball. Rodney was clearly not doing well with control.

The Royals very probably would have lost whether or not Aoki had bunted. And they might have won after he sacrificed. Maybe if he had swung away, he would have grounded into a double play. Maybe Billy Butler or Salvador Perez would have gotten a hit after Hosmer walked and tied the game or even put the Royals ahead. “Can’t predict baseball” is as obvious as it is trite. Overall, though, the decision to have Aoki sacrifice bunt with one on and no one out seems to have hurt the Royals chances, and a deeper examination does not really help Yost’s case.