“I was gonna lay down the bunt, but then I got high”

I was watching a Cardinals game a couple of days ago (I believe it was the Sunday night one against the Mets) when one of the announcers mentioned that it was harder to bunt pitches that were elevated in the strike zone. The idea is that, since a successful bunt is almost always going to be on the ground and there is a very strong relationship between vertical location and ground ball percentage across all pitch types, it’s harder to bunt pitches up in the strike zone. That makes sense, and I’ve heard it a million times in games; however there is the whole question of whether or not it is actually correct.

My method of investigation was pretty simple. I looked at all attempted bunts by pitchers in 2009 and measured whether or not they resulted in a sacrifice or a hit. Those were considered “successful” bunts. There were 2244 attempts last year overall and 63% of them were successful. I then grouped that by the vertical height of the pitch, in intervals of .33 feet. Here is a graph of what I found with the height of the pitch (in feet) on the x-axis, the percentage of bunt attempts what were successful on the y-axis and the standard error range in gray:

image

As you can see there is actually a slight upward trend in the graph. In other words, the higher the pitch was the in the strike zone the more often it was bunted successfully. The 2008 data shows a similar trend as well.

Now this brief analysis leaves out one key aspect of bunting – foul balls. Most people would consider a foul ball on a bunt attempt a failure; however, foul bunts with less than 2 strikes are not recorded by the GameDay operators. Only at bats that ended with a bunt are. So while based off of this analysis we can say that when a bunt is put in play there is little to no relationship between it’s vertical location in the strike zone and its odds of success, that doesn’t not necessarily mean that applies to all bunt attempts. Still, it appears that there isn’t much truth to that bit of conventional wisdom, at least in regards to pitchers.


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Peter Jensen
13 years ago

Nick – Retrosheet and MLBAM record all foul bunts in their pitch sequences as a pitch type “L”.  There were 645 by pitchers last year of which 82 resulted in a third strike.

Nick Steiner
13 years ago

Thanks Peter.  I’ll check out how that affects the numbers when I get home.

Kanka
13 years ago

When the batter squares to bunt, they normally start with the bat shoulder- or chest-high.  (I was always taught to square with the bat at the top of the strike zone; if the pitch was above your bat, it was a ball.)

It seems then that the success of a bunt is inversely proportional to how far vertically the bunter has to move the bat to make contact.  That may also explain the spike at 3.5+ feet – even the most inept bunter can lay one down 2/3 of the time if he doesn’t have to move the bat at all.

James
13 years ago

I also imagine it’s harder to pop a bunt up (the worst result possible I’d imagine) if it’s higher up in the strike zone. The more you have to move, the more likely you are to overshoot or undershoot the ball and pop it up or send it straight into the ground.