PHOENIX -- The D-backs are in the process of building a humidor at Chase Field with the goal of improving the grip that pitchers are able to get on the baseball.
The only other humidor used in Major League Baseball is at Coors Field in Denver, which is the one Major League city with a higher altitude than Phoenix.
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Major League Baseball guidelines say that baseballs should be stored at 70 degrees with about 50 percent humidity. That isn't possible in the dry desert air, particularly during the hot summer months without the help of a humidor.
"We have to store baseballs in a certain environment," D-backs general manager Mike Hazen said. " ... The ability of the pitchers to grip the baseballs, especially through the summer months when it gets extremely hot and dry, no matter what we've done in terms of rubbing them up the right way, it seemed to be a challenge. This seemed to be the solution that we could come up with."
The construction of the humidor should take about another four to six weeks, and it will need to be tested to make sure it is up to specifications.
In addition, Major League Baseball requires the balls to be stored in the humidor for at least two weeks before use in a game.
The Rockies introduced their humidor in 2002 and scoring initially did go down as a result, but as time went on the impact seemed to lessen. Hazen said the D-backs did talk to the Rockies about their experience before making the decision to install one.
"The largest impact was the ability of the pitchers to consistently grip the baseball a little bit better than they had without it," Hazen said of what the Rockies told him. "We're in a little different environment than Colorado, so it's not the exact [comparison], so we can't just take their data. It's something we're going to continue to watch and study as we go through."
D-backs left-hander Jorge De La Rosa pitched for the Rockies for nine seasons, but he said he did not know if the humidor made a difference because he had never pitched there before it was installed.
"Like they say, if you make a good pitch, you're going to get outs," De La Rosa said. "I don't think it's going to be a lot of difference."
Hazen said the D-backs did not consult with any current pitchers or players about the decision, but they did ask former pitchers and they described the balls being like "cue balls" and difficult to grip.
Current pitchers like Patrick Corbin agree with that.
"Some of them are slick," Corbin said. "You've got to kind of rub it up when you get the ball back pretty much every couple pitches when you get a new ball. If it helps out there that would be great. The ball does feel a little dusty at times I would say."