Pitch Location & Groundballs

Last week Baseball Analysts published my article Generalities in Pitch Location, which led Tangotiger to ask the following question:

“…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 “true” 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.

MLB GBP Location.png

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).

Webb GBP Location.png

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.

Zito GBP Location.png

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.




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David Appelman is the creator of FanGraphs.


One Response to “Pitch Location & Groundballs”

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  1. missionhockey21 says:

    I would tend to agree with your last statement. If inducing the groundball was as simple as targeting specific locations, then baseball would be a much simpler game to figure out as a pitcher. A pitcher with the kind of godly GB/FB that Webb shows also shows through his charts (and just any viewing of him actually pitching), that he can break the taboo often times with getting away with a pitch higher in the zone for various factors be it more knowledge of the hitter he’s facing, pitch selection plus pitch location, velocity, etc to more often see a bouncer or a roller than the average pitcher.

    With these being two very good pitchers, I wonder if there is anymore of a visible impact for pitchers of a lower success rate. Such as Mark Mulder who is peripherals aren’t near as good as Wood’s for his last successful year in 2005 where he posted a GB/FB close to 2.80 IIRC. Obviously he isn’t on the same level as Wood in his ability to induce the grounder (especially since that was quite a spike from his career average), but there is a difference of talent there and I wonder if it would be more apparent for him.

    Either way, interesting article David.

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