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Hoffman’s Fastball and HR Prevention

I was poking around the pitch type leader boards and noticed an interesting fact: Trevor Hoffman had the best fastball of all qualified relievers in 2009. His 85mph pitch beat out the likes of Phil Hughes‘s and David Aardsma‘s, which were almost 10 mph faster.

When he re-signed with the Brewers I noted that he has, over the course of his career, been able to maintain a HR/FB well below the 10% expected value. Playing in Petco for a big part of his career no doubt helped, but beyond that it seems like Hoffman has the ability to depress his HR/FB, which runs counter to some of the prevailing ideas about a pitcher’s ability to control his balls in play.

These two facts, the fact that he had the best fastball of 2009 and his historic ability to depress, inspired me to look at Hoffman’s pitchf/x numbers in a little more depth. Let me say that this analysis just scratches the surface of what makes Hoffman so great. His changeup is devastating and I am sure plays a big role in his HR prevention and probably makes his fastball better. In addition, his fastball has a lot of “rise,” which plays a big role in his high IFF%. But I am going to focus on HR prevention with his fastball, and specifically HR prevention against LHBs.

A lot of attributes determine if a pitch is going to be hit for a HR, but one of the most important is its location. Obviously the height of the pitch plays a big role, but here I am going to look at the horizontal location of the pitch. Here is how HR/FB varies for LHBs against all pitchers (not just Hoffman).
So pitches middle-in are hit for HRs the most often. Now let’s look at where Hoffman locates his fastball. Gold is Hoffman and gray the average four-seam fastball to a LHB.
Hoffman’s distribution is much narrower than average. He has been very good at locating his pitch in the same horizontal area with little spread. This should not be surprising: the fastball is just 85 mph, so for him to be successful, he needs that pinpoint command. And he puts the pitch about as far away as he can and still be in the strike zone. That is where LHBs have the least power.

I usually just display the 2-foot strike zone that John Walsh described, but in this graph I add the dotted line for the specific strike zone to LHBs. The zone is called differently to LHBs, with the outside and inside edge shifted away. That makes Hoffman’s pitch locations even better. He pitches more to the extreme outside where umpires often call pitches 14 or so inches from the center of the plate strikes against LHBs.

As I said, there is a lot going on and this just scratches the surface, but Hoffman’s ability to locate his fastball very well on the outside quarter of the plate to LHBs, I think, plays a huge role in his abnormally low HR/FB rate.