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February 3, 2005

Crooked Numbers

Park Effects on Pitcher Types

by James Click

After taking a detailed look at the Dodgers’ acquisition of Derek Lowe, a number of readers wrote in to discuss the hundreds of new field-level seats being added to Dodger Stadium. The general question was: “Did I consider this in my research, and if not, how do I think it will affect Lowe and the Dodgers in general?” The answers I provided over e-mail were: "No, I didn't, and it should increase general offense in the park. Because that should mainly be a result of a few more foul pop-ups lost to the seats, Lowe would be affected less by these changes than other pitchers because he’s such an extreme groundball pitcher."

This got me wondering about parks and the application of park factors. Park factors are not simply for adjusting runs; they can also be applied to individual statistics such as singles, doubles, triples, home runs, etc. While most parks see a consistent difference in most offensive categories (Coors Field and Bank One Ballpark increase all offensive measures while decreasing strikeouts), some stadiums have differing effects on similar parts of offense. As I discussed last time, Dodger Stadium differs from Fenway Park in that it suppresses doubles and triples, but allows more home runs. Additionally, Comerica Park and SBC Park allow nearly double the league average of triples while suppressing all other forms of offense.

Generally what happens at this point is people look at those factors and say “Well, that makes sense. Fenway Park’s Green Monster and cavernous center field should increase doubles and triples while Dodger Stadium’s shorter center field allows the center fielder to play more shallow and cut off a few more drives to the power alleys.” Everyone nods in agreement, noting how that makes sense.

Of course, the one thing people rarely talk about with park factors is the infield, because it’s the only part of the ballpark mandated to be exactly the same dimensions everywhere. Outfields can be all sorts of sizes and shapes within the league guidelines (and sometimes not), but it’s always 90’ to first, 60’6” to the mound, and, if my math is correct, 127’3” from home to second. While the surface can be different, and while some teams intentionally keep their grass short or long, infields are all very similar and generally considered not to have as much of an effect on park factors as outfield dimensions.

It stands to reason then that groundball pitchers should be less affected by park factors than flyball pitchers. By keeping the ball on the ground, groundball pitchers should see significantly more balls fielded in the more regulated infield and fewer balls rattling around the unique confines of each outfield.