Saturday, October 31, 2009
Should Jeter have bunted?Posted by Colin Wyers
It's a popular topic. Let's ignore the decision to bunt with two strikes - even Jeter admits that was a mistake - and look at the decision to start the PA bunting.
So what's the most salient fact about Derek Jeter bunting? He reaches base safely a third of the time when he lays down a bunt fair. This shouldn't surprise anyone - Jeter is a gifted singles hitter who is also perenially one of the league leaders in reaching base on an error.
So let's look at run expectancy. As Bee notes:
According to run expectation, with runners on first and second and no out, a team is expected to approximately 1.5 runs in an inning. When there are runners on second and third with one out, the run expectation actually goes down to 1.4.
Yes. But - that ignores the possibility of Jeter reaching safely. Let's simplify this and look at the odds of Jeter reaching base and the runner at second holding up at third (there is of course the odds of the runner at second scoring and of being thrown out, among other things):
(1.41-1.48)*2/3+(2.28-1.48)*1/3 = 0.22
So - and again, we are drastically oversimplifying here - the average run expectancy of a bunt there was .22 runs. For the basis of comparison, over the past three seasons, Jeter has averaged about .15 runs per plate appearance. Again, this is a drastically oversimplified analysis (MGL is the crown prince of not simplifying bunt analysis, if you're interested in such things).
But it's quite frankly silly to claim the Jeter bunt was a bad idea without looking at the odds of him bunting for a hit (or reaching on an error). That goes double for anyone quoting his batting average with RISP. I advise anyone who cares about this sort of thing to go read The Book.
Colin Wyers knows exactly how much of a nerd he is. He is very interested in hearing about any other concerns you may have; you can reach him by e-mail, and he will try his best to respond in a timely fashion. He also blogs at Statistically Speaking.