“…how often does Brandon Webb and his brothers get a GB on balls thrown down and balls thrown up the zone. That is, are they â€œtrueâ€ groundball pitchers, who can get batters to hit the ball on the ground, because they can. Or, are they groundball pitchers, as a byproduct of them throwing the ball low?”
First let’s take a look at ground ball percentage by pitch location on a major league level.
I don’t think there are too many surprises here. The lower the pitch, the greater the chance that it will be hit on the ground. So, let’s look at what Brandon Webb‘s (extreme groundball pitcher) chart looked like the past two season, compared to say Barry Zito’s (extreme fly ball pitcher).
Starting with Webb, we can see that no matter where he throws the ball, there’s a pretty good chance it will end up being a groundball. Zito on the other hand, will have a greater chance of inducing a fly ball despite the location of the pitch.
Now if you were to calculate a so called, “expected” groundball percentage based on the pitch locations of balls hit into play for a particular player and the league average groundball percentage for that particular pitch location, you’d see that Webb has an expected GB% of about 48%, while Zito’s is 44%.
All in all, a pretty similar “expected” groundball percentage based on pitch location and major league averages, but in reality the two couldn’t be further apart. Webb’s actual GB% the past two years is about 66% with Zito’s being around 39%.
It would seem, at least in the case of these two pitchers, that their ability (or lack there of) to induce groundballs is not entirely a function of where they throws the ball, but probably reliant on several other factors.
David Appelman is the creator of FanGraphs.