THE BOOK--Playing The Percentages In Baseball

Fascinating. It implies that many foul balls are just inadequate contact, not deliberate attempts to “waste” a pitch. But then I’d want to look at the subclass of hitters with high contact rates and high FoulBall% vs. those with high contact rates and lower FoualBall%. Is FB% then predictive of anything?

One thing I found interesting is that apparently6 a foul ball is much more like a swing and a miss than a swing and a ball in play. I’m not sure that that is intuitive…

I think the overall trend that a foul ball appears to be inadequate contact is misleading.

As Pizza Cutter found, the correlation apparently isn’t negative for 2 strike counts. Well, most hitters probably are not going to foul off a pitch intentionally on a zero or one strike count, so I’m not even sure looking at those counts is relevant. If a player with better bat control (and presumably better contact skills) hits the ball, it is probably much less likely to go foul by random chance than a ‘swing for the fences’-type hitter. So a negative correlation is definitely expected.

Now, if get to a two strike situation, the guy with better bat control can more easily foul off pitches he doesn’t like. The swing for the fences guy might be able to do that too, but either way he is stilled expected to foul off some pitches but perhaps at a worse rate than the guy with good bat control. Hence a positive correlation is expected.

So why the overall negative trend? A player with better bat control, on average, is more likely to put the ball into play on a zero or one strike count, whereas the swing for the fences guy will work the count to wait until he gets something good. So the the high contact guys most likely have a disproportionately high number of foul balls in one or two strike counts (while the lumbering oaf slugger probably is about the same in any count). This lead to the overall negative trend.

Obviously, this is all conjecture, and my sole empirical proof lies in those articles.