MLB to Mandate That Baseballs Are Stored in Air Conditioned Room for 2018

In a potential effort to combat the surge in home runs, MLB is mandating that each team store balls in an air conditioned and enclosed room for 2018.

PHOENIX — For the first time, Major League Baseball is standardizing how its 30 clubs store baseballs, according to several sources familiar with the plan distributed to clubs. Baseballs must be stored in “an air conditioned and enclosed room” this season.

Major League Baseball will install climate sensors in each room to measure temperature and humidity throughout the 2018 season. That data will be used to determine whether a humidor is necessary in individual storage rooms for the 2019 season.

The Arizona Diamondbacks are installing a humidor this season. Their room is designed to store baseballs at the MLB recommendations of 70 degrees and 50% humidity. The Colorado Rockies have used a humidor since 2002 for the same reason Arizona is installing one: to combat the effects of storing baseballs in dry conditions. Lack of moisture makes baseballs slicker and gives them a higher coefficient of restitution, or liveliness.

MLB teams go through more than 260,000 baseballs in regular season games, or about nine to 10 dozen each game. Pallets of baseballs, boxed by the dozen, are shipped to clubs at various times of the year. They sometimes sit for months before usage, when they are unboxed and prepped before games with rubbing mud to reduce the shine and slickness. Until now, the baseballs were stored at the discretion of the club, leading to variances in temperature and humidity, which affect the flight of the ball.

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The move to standardize the storage of baseballs comes after a season in which MLB shattered its all-time home run record, pitchers complained of low seams and tightly wound balls, and the slickness and uniformity of baseballs used in the World Series came into question.

Commissioner Rob Manfred said Tuesday that MLB commissioned a research project after last season to study the composition, storage and handling of the baseballs. He said that investigation is not yet completed. “I’m not at the point to jump that gun right now,” he said about the findings.

MLB also is continuing to investigate the use of tackier baseballs, such as the kind used in Japan that do not require rubbing mud. Those inquiries are preliminary, such as trial use by pitchers throwing bullpen sessions or in low minor leagues.