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10/13/07 10:00 AM ET

Rox humidor could be trendsetter

Monitoring of climate's effects on ball an 'emerging science'

DENVER -- Rockies pitcher Josh Fogg made an odd proclamation earlier this season about the once homer-friendly Coors Field.

Fogg called Coors Field a "pitcher's park."

"I like pitching here," he said. "It's a big yard. You earn your home runs here now. There's days that the ball flies out of here, but you've got to hit a ball good to get it out of here."

Before suggesting Fogg get professional psychiatric assistance, just take a look at the numbers since the Rockies started keeping baseballs in an atmosphere-controlled climate at Coors Field in 2002.

Since then, the Rockies have kept baseballs in an atmosphere-controlled climate, known locally as "the humidor," to keep them from shrinking, hardening and losing friction in Colorado's unique environment. Major League Baseball stopped short of mandating all teams adopt such an apparatus, but the move toward standardization continued in 2007, as all 30 teams are storing baseballs in controlled environments.

The first year the humidor was used, 232 home runs were hit at Coors Field, an all-time low for the ballpark. Home run totals steadily dropped until this season, when 185 balls left Coors Field, up from 168 in 2006.

The Rockies file weekly reports with Major League Baseball, and MLB operations will travel to Coors for periodic checks on the procedure. Jimmie Lee Solomon, MLB executive vice president, baseball operations, said the Rockies are monitored more than any other club.

Solomon called the monitoring of a climate's effects on baseballs, and in turn how the ball performs in games, "an emerging science." But the eventual goal is to make sure that the baseball in all venues stays at Rawlings' specifications, presumably with all teams storing them in a standard chamber.

Before the humidor's advent at Coors Field, games in the Mile High City could sometimes resemble Nintendo baseball. Coors Field has three of the top four homer totals in Major League history. An MLB-record 303 homers were hit in 1999, 271 in 1996 (third most) and 268 in 2001 (fourth most). US Cellular Field hosted 277 homers in 2004.

The humidor has helped changed things to totals more in line with other MLB parks.

Homer haven no more
Here's a year-by-year breakdown of home runs hit at Coors Field during the regular season since the park opened in 1995. The humidor was installed prior to the 2002 season.
YearHome runs
"It's given our pitchers a level playing field for the first time since the inception of the ballpark in 1995," Rockies manager Clint Hurdle said. "Little did we know, for a number of years the balls were shrinking, traveling farther, and we would go 'Whoa' and 'Ahh, look at that one!' We had no clue. Nobody did."

Many still believe that Coors Field is home of the long ball and a hitter's park, an assumption that still holds some validity, but not much. The Rockies and their opponents hit 2.26 homers per game this season at Coors Field, which ranked 10th among Major League ballparks. They also combined to score 10.68 runs per game at Coors, which ranked fourth.

Rockies pitchers, however, don't seem to suffer like they did before the humidor. The staff gave up 82 homers this year at home and 82 on the road. The team's ERA at home and on the road were almost identical -- 4.34 at Coors compared to 4.29 on the road.

The Rockies pitchers had the lowest ERA in the National League after the All-Star break at 3.86, and they no longer have to watch pop flies carry into the stands -- with many thanks to the humidor.

"Besides leveling the playing field at home, it cut down the drastic difference when we would travel on the road," Hurdle said. "Because we've been challenged dramatically on the road since the organization's inception, and that has gotten better along about the time of the humidor's existence. So I think they worked hand-in-hand, made the game a little more normal, both places."

C.J. Moore is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.