Phoenix humidor might lead to big change

Unlike me, Nick Piecoro's done some actual reporting:

    The Diamondbacks are considering storing their baseballs in a humidor next season, and University of Illinois physics professor Alan Nathan wants them to proceed with caution."They ought to consider carefully what they're doing, that's for sure," he said.According to Nathan's research, a humidor might not just nudge the balance of power a little toward pitchers. It could vastly alter the landscape at one of baseball's most hitter-friendly environments.--snip--

    Nathan said that when baseballs that had been at 30 percent relative humidity were stored for two weeks in a humidor at 50 percent, the balls' speed off the bat decreased by about 2.5 mph, which they say comes out to a 14 foot dropoff on a typical long fly ball.

    "Our rough statistical estimate was that (14 feet) will decrease the number of home runs by about 25 percent," Nathan said.

    As it turns out, that's exactly the reduction seen in home runs at Denver's Coors Field since they began using a humidor in 2002.


    Rybarczyk, like Nathan, hopes the Diamondbacks do their homework before determining what levels to set their humidor, assuming they get one. Coors Field's humidor is set at 70 degrees and 50 percent humidity, the specs Rawlings uses when making the balls.

I'm under the impression that the Diamondbacks don't have any choice in the matter. Major League Baseball simply won't allow teams to adjust humidor settings at a whim. Coors Field's humidor is set where it is because it's (supposedly) consistent with the manufacturing process. Do anything else, and you're open to charges of home-field manipulation. Allow a team to change the settings, and they'll go up and down depending on who's in town and who's pitching. Major League Baseball won't allow that, any more than it'll allow teams to move the outfield fences during the season.

Nathan says a humidor would cut home runs by 25 percent. Rybarczyk, looking at nearly five years' worth of home runs (2006-2010), estimates a humidor would have cut the homers by 38 percent.

The Diamondbacks could probably live with 25 percent. They would probably be alarmed by 38 percent.

Of course, these are just best guesses. My guess is the range is actually somewhere between 20 and 40 percent, and that range might be larger than management's willing to risk.

I'm still not quite sure what all the fuss is about. In 13 years, all in this same stadium, the Diamondbacks have seven winning seasons and four division titles. Their problem these last couple of seasons hasn't been the ballpark. It's been a shortage of great players.