F/X VisualizationsSeptember 18, 2009
Home Runs: Where Did You Come From, Where Are You Going?
By Dave Allen

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.


Something strange here. Last week I requested you look at Joe Mauer. I'm repeating the request. Reason: I know 23 of his 27 HR's are to left or center. And he is not alone. Both Adrian Gonzalez and Ryan Howard prefer to go the other way as well. Remove the three of them from your last chart and there will be almost nothing left over there.

Yeah I looked at some of the top LH HR hitters and Branyan, Pena, Morneaum, Lind and Fielder are pretty much dead-pull. But then as you mention Mauer is almost all opposite field. I think you are right he would be really interesting to look at. I will probably do that in the near future and put it up at FanGraphs.

I agree with you on 4 out of those 5. But take another look at Lind. He has the closest I've seen to a uniform distribution across all fields.

Opps, yeah. Lind's are very evenly distributed.

I'd like to see the first chart with separate curves for LHP and RHP. I know you imply that it doesn't matter, but seeing is believing.

It would be interesting to see whether there are some park effects where RF is easier to get over the fence than LF (wind, distance) on an overall league basis so that an equal RHB pulls fewer outside pitches over the fence than an LHB. Or whether LHB's crowd the plate a bit more on avg due to the predominance of RHP's.