Last April the Yankees were targets of widespread criticism. It wasn’t because of their lavish off-season, though, but rather because of their new palace in the Bronx. While the old Yankee Stadium was known as a haven for left-handed hitters, who could pop home runs over the short porch in right, the new Stadium seemed to exaggerate that effect. Both the Yankees and their opponents cleared the fence frequently last April, with the Yankees hitting a home run every 19.87 PA, while opponents hit one every 23.92 PA. The effect persisted in May, with only slight changes in the home run rates. Many thought that the Stadium was clearly hitters’ park, and some went so far as to call it an embarrassment.
In The Star Ledger, Marc Carig tackles the topic of how Yankee Stadium will play in 2010. He notes the trends that I wrote about a few weeks ago on ESPN. Once June hit the home run rate dropped. Opponents felt the brunt, dropping to one home run every 41.83 PA, and staying in the mid-30s for the rest of the season. The Yankees only saw a slight drop-off, though. Their June, July, and August numbers were only slightly worse than the April and May ones. I think this illustrates the issue.
The perception of Yankee Stadium as a bandbox started in April, and was based mostly on a game where Cleveland hit six home runs. Tampa Bay also had a game where they hit four homers. Remember, though, that opponents only came to the plate 311 times in April, hardly a meaningful sample. Opponents hit 13 home runs, but six of them came in that Cleveland game, where Chien-Ming Wang and Anthony Claggett served up the taters. May isn’t quite as explainable, as opponents hit 29 home runs in 672 plate appearances, a slightly quicker pace than April. But, again, their rate dropped off considerably after that.
As I noted in the ESPN TMI article, the Yankees hit a ton of home runs at the Stadium because the team was built to do just that. In addition to the three lefties — Matsui, Damon, and Cano — the lineup featured four switch hitters: Teixeira, Cabrera, Posada, and Swisher. Those four have all hit for more power from the left side in their careers. The plan worked, too, as each of them outpaced their career slugging numbers from the left side. Combined with the raw power of Alex Rodriguez and Derek Jeter’s excellent power numbers to right, the team was not only built for its home park, but was also well-rounded enough to succeed on the road.
We still don’t know if the early season power numbers from last season were an aberration or if they represent some kind of weather pattern at the Stadium. That’s why park factors are best examined using three-year samples. We just don’t know what caused the balls to leave the yard. Were the pitchers just not used to pitching at the park, as Joe Girardi says? Or is there an environmental effect that pushes the balls out? We’ll have a better idea after this April and May, though we still won’t have the full picture. That will take another year or two to determine.