F/X Visualizations September 18, 2009
Home Runs: Where Did You Come From, Where Are You Going?

Last week I looked at Carlos Pena's HRs, examining the angle in play based on the horizontal location of the pitch. Today I am going to do so for all batters. First off it is important to understand how pitchers pitch differently to RHBs and LHBs. Here is the frequency of fastballs thrown to RHBs and LHBs by horizontal location. I flipped the horizontal location for lefties so the inside of the plate is on the same side of the graph for both groups.

As you can see pitchers throw much further away to lefties than to righties. This is true of both LHPs and RHPs, so it is not an artifact of say opposite handed at-bats tending to be pitched farther away and there being more RHPs. Pitches to RHBs are centered only slightly away of the center of the plate. Strangely the power profile of lefties and righties suggest that pitchers should do the exact opposite.

Although both have more power inside, the difference is more pronounced for RHBs that for LHBs. So that RHBs have slightly more power inside than LHBs inside, while LHBs have much more power away than RHBs away.

So we have a situation in which LHBs seen most of their pitches far away in the zone and have relatively good power there, while RHBs see pitches most of their pitches closer to the center of the plate, maybe shifted slightly outside. But their power is much greater middle-in.
This section is a correction of the original version.
The result for RHBs is that most of their HRs come from the middle of the plate, where they see a lot of pitches and still have good power.

The highest density of HRs are on pitches middle-in and most of those are pulled to left field. Even pitches that are slightly away are generally pulled. It is a little hard to see, but most of the opposite field HRs are on away pitches. That is there are few steep lines going from the bottom left of the graph to the top right of the graph.

Now, recall that lefties see mostly outside pitches, and that they have fairly good power on those pitches. The result is that most of their HRs come from pitches away.

You can see the higher density of HRs middle-away compared to the RHBs higher density middle-in. With that exception the image is largely a mirror image of the RHBs image, with most of the HRs pulled to right field. This graph also shows that my conclusion from last week probably wrong, Carlos Pena is really not that extreme in his HRs. I do think that Pena's HRs did come even more away than most lefties, but this does show that Pena is just an exaggerated version of what most average lefties looks like, not a major outlier.