And That’s Why They Play the Game
The Nationals just had a great comeback against the Marlins this afternoon. The final game graph (unofficially) looks like this:
The Marlins newly acquired Jorge Julio pretty much blew the entire game for them with a WPA of -.903 wins. The Nationals low point in the game was in the bottom of the 6th with 2 outs when they had a mere 3.7% chance of winning the game.
But let’s draw our attention to one very specific play at the end of the game: the sacrifice bunt when the score was 6-5 in the bottom of the 9th. Before the sacrifice bunt there was a runner on first with no outs. The Nationals at the time had a 34.4% chance of winning. Manny Acta, the Nationals new manager, had Felipe Lopez hit a sacrifice bunt. It was successful, but it didn’t improve their chances of winning the game. Instead of increasing their chances, it actually decreased it by 6% to give the Nationals a 28.8% chance of winning.
If you were watching the game on FanGraphs, you got to see exactly why the following is true:
To quote The Book: “With a non-pitcher at the plate, and a runner on first and no outs, advancing the runner in exchange for an out is a terrible strategy. It significantly reduces the RE in almost any run environment. It also reduces the WE in almost any run environment, even late in a close game.”
Fortunately for Nationals fans (while unfortunate my hopes and dreams), they ended up winning anyway.
Tim Daloisio said,
April 4, 2007 @ 6:47 pm
Just a fantastic example and explanation of a strategy that is employed far too often.
Dave, is there any way you could create live WPA widgets that we can embed in our blogs? I would love to add it into the game posts for the Red Sox Times.
David Appelman said,
April 4, 2007 @ 8:24 pm
Thanks Tim.
Widgets…. hmm… I’m not sure if my stats license currently permits me to do that. I’ll need to look into it. It’s a good idea though and if it’s possible, maybe I’ll be able to get something working in the next month or two.
Scott M. Collins said,
April 5, 2007 @ 11:58 am
I agree with the book and I understand the 6% reduction in win probability. However, in the bottom of the 9th, down by only one run, just trying to get at least the tie, with 3 good, (usually) patient, hitters coming up? I gotta think that Acta made the right call for the situation. And I’m usually a bunt hater.
MGL said,
April 5, 2007 @ 1:05 pm
The quote above from The Book refers to “a successful sacrifice bunt” wherein the batter advances the runner in exchange for an out. That is NOT the same thing as ATTEMPTING a bunt, which is what drives the decision that the manager has to make. Depending on the batter (his speed and bunting ability), to a small extent the runner, and to a large extent, the position of the infield (how much they are anticipating the bunt), the average result of a sacrifice ATTEMPT can be better or worse (or the same of course) than an out and a runner advance. That “average” result (the weighted WE average of all the possible results - e.g., single, error, GDP, etc.) is what determines whether a bunt attempt is warranted or not. Then there is the additional consideration of “game theory” (essentially preventing the defense from playing completely or predominately back or in because they always know what you are going to do or they have a very good idea as to what you are going to do). For a complete discussion and analysis of the sac bunt, read the sac bunt chapter in The Book.
tangotiger said,
April 5, 2007 @ 3:10 pm
Can you guys tells us how the fielders were positioned? Was it an obvious bunt attempt? And, how was the batter setup? Was he specifically trying to force “the perfect bunt”, at the risk of him not even having a chance at being safe at 1B? That is, was it a straight “you guys know I’m bunting, I’m going to bunt it as best as I can, and I won’t even bother trying to run it out, because the play will be that bang-bang”?
Scott M. Collins said,
April 5, 2007 @ 3:30 pm
IIRC, it was a straight up “hey guys I’m bunting the guy from first to second.” No real attempt at a bunt single.
In the first bullet point here (http://dcbb.blogspot.com/2007/04/fouled-off-bunts-whats-double-switch.html), Chris Needham points out that win % is somewhat irrelevant in this situation as the Nationals were playing for the tie to extend the game at home. If they were on the road, that’s more of a dubious move.
David Appelman said,
April 5, 2007 @ 3:33 pm
Looking again on MLB.tv, he wasn’t showing bunt the entire pitch, but switched fairly early in the delivery. He showed bunt on both pitches he saw and ended up bunting the second pitch down the first base side, about midway between the mound and home plate, and the mound and first base. Third baseman was on the edge of the infield grass on the second pitch. He was out at first by maybe 1 and a half steps. Lopez was really hustling to first.
MGL said,
April 6, 2007 @ 10:36 am
Scott, the WE INCLUDES “playing for the tie, etc.”
Personally, I don’t know that “how it looks when you lay down the bunt” makes a difference in terms of how often you get the extra singles, etc. It may simply be the position of the infield, your bunting ability in general, and your speed. IOW, a “by the book” bunt may be better than a “bunt for a single” in a sac situation because you may not want to get too many foul balls.
The other (and very important) thing to remember has to do with game theory. You cannot necessarily evaluate an alternative (in this case, decision to bunt) in its own context. IOW, a non-bunt may have been correct if you know all the numbers and do the appropriate calculation, but you still may have to bunt some percentage of the time (it might be 10%, it might be 90%, depending on the numbers) to “keep the defense honest.” This is a tricky concept to get your arms around. We touched on it in the “game theory” chapter of The Book. A good example is with pitch selection. Let’s say that you normally would throw a pitch out of the strike zone with an 0-2 count against a particular batter. Well, you can’t do that ALL the time! If you did, the coach could and would just instruct the batter to never swing on 0-2. So let’s say that the correct thing to do is to throw a pitch IN the zone 20% of the time (I don’t know whether that is right or not). Every time you see a pitcher do that, it will LOOK like he just made a bad decision, and if you are the pitching coach you will likely chastise him. Of course, the pitcher, if he understands game theory, will simply say, “Coach, that was my “20% pitch - 80% of the time I throw one out of the zone!” And he would be right of course!