Those Home Run Blues

We’re about two months into the season, and it’s not a bad time to look which pitchers are allowing too many home runs. Fortunately, there’s a useful metric on FanGraphs to do just that. It’s called HR/FB and while I’m sure many of you are familiar with it, here’s a brief summary of how it works.

There’s been a number of studies done on HR/FB and for the most part, they conclude that pitchers do not have control over how many home runs they allow on outfield fly balls. Your typical starting pitcher should be expected to have a HR/FB of around 10% every year. Anything that deviates from 10% could be contributed to the park he pitches in, or to “luck”. So let’s look at who has been allowing an inordinate number of home runs this season:

Roy Oswalt (23.4%) – Oswalt leads baseball with a rather ridiculous HR/FB rate. Basically one in four of his fly balls have become home runs. I don’t care where he’s pitching, this is just Oswalt having some terrible luck. He’s never had a HR/FB above 12.9% to end the season. A couple weeks ago, Eric Seidman asked if you should trade Oswalt in your league; the answer is still no and now is another prime opportunity to go acquire him.

Brett Myers (21.4%) – Sure he plays half his games in Citizen’s Bank Park and he does have a career HR/FB of just over 15%, but 21% even for him seems quite high. He probably isn’t due for such a drastic adjustment as Oswalt, but I’d imagine it should start to trend towards his career average. He hasn’t allowed a home run in his last two starts either, so perhaps he’s well on his way to normalcy.

Carlos Villanueva (16.9%) – Currently, Villanueva leads baseball with a 2.09 home runs per 9 innings. He’s about as much as a fly ball pitcher as he is a groundball pitcher so he really shouldn’t be tied for 5th with most home runs. While Miller Park isn’t all that favorable to fly balls, he should be able to do considerably better in the home run department and decrease is ERA by more than a little come season’s end.

Johnny Cueto (16.4%) – It looks like the phenom has himself a bit of a home run problem. Since he hasn’t been around for very long, it’s a little tough to say if this is just a luck thing, or of it’s a real problem. I’d venture to say it has more to do with luck then anything else, even if he does play in a park that is prone to home runs. Unfortunately, Cueto is an extreme fly ball pitcher and isn’t expected to be particularly stingy with home runs in general.

Mike Mussina (16.4%) – We all know about Mussina’s decline in fastball velocity. John Walsh’s research suggests that mis-located fastballs of the slower variety could certainly cause an increase in home runs and it’s possible that could be happening to Mussina. I still think his HR/FB should drop as the season continues, but it’s hard for me to be enthusiastic about.

Johan Santana (15.9%) – Santana developed a home run problem last year and it seems to have continued into this year. Shea stadium is slightly worse for home runs than the Metrodome, but it really doesn’t explain such a high HR/FB. It’s hard to imagine it won’t decrease as the season goes on, but unless it drops back down to around 10% or lower, it will be difficult for him to return to sub-3 ERA levels.





David Appelman is the creator of FanGraphs.

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