Ballparks with retractable roofs or side panels, such as Chase Field in
Arizona, are subject to rules on when they can be open and shut
MLB has rules for nearly everything, and opening and closing the roof in retractable-roofed stadiums is no different. No one has <ahem> raised the roof on these rules yet, but they do go to show you nothing—and we me nothing—is left to chance in Major League Baseball.
The following is from the 2010 Red or Green Book distributed to the media:
MLB GUIDELINES FOR MOVEMENT OF RETRACTABLE ROOFS
Championship Season (regular season)
The decision to open or close the roof prior to the start of the game resides with the home Club. Each Club with a retractable roof shall file with the MLB Baseball Operations Department a list of the criteria it intends to use during the championship season to decide whether to begin a game with its ballpark’s roof open or closed. The home Club should inform the umpire crew chief and visiting Club if it intends to move the roof during the game.
A. Closing an Opened Roof
If the game begins with the roof open, it may be closed only in the event of impending rain or other adverse weather conditions that may affect play or spectator comfort. If the home Club believes such conditions exist, the home Club shall confer with the umpire crew chief, who shall in turn inform the visiting Club. The visiting Club may object, if it feels a competitive imbalance will arise. In that event, the umpire crew chief shall make the final decision. If there is no objection, the decision to close the roof rests solely with the home Club.
B. Opening a Closed Roof
If the game begins with the roof closed, it may be opened if, in the opinion of the home Club, the climatic environment is such that fan comfort and enjoyment will be best served by opening the roof. A closed roof may not be opened on the grounds that weather conditions may affect spectator comfort after the conclusion of the sixth inning. Prior to opening the roof, the home Club shall confer with the umpire crew chief, who shall in turn inform the visiting Club. The visiting Club may object, if it feels a competitive imbalance will arise. In that event, the umpire crew chief shall make the final decision.
C. Roof Movement
The roof may be moved only once during the game (i.e., once closed, it may not be re-opened, and once opened, may not be re-closed) unless inclement weather or other adverse weather conditions indicate otherwise. Clubs should be very cautious of opening a closed roof if the possibility of inclement weather exists.
The movement of the roof must commence at the conclusion of an inning, unless weather conditions are such that the umpire crew chief deems it necessary to close the roof immediately so that play is not interrupted. The movement of the roof shall be continuous and play will not be stopped.
Wall Panels (Milwaukee and Arizona)
The home Club shall decide whether to open or close the wall panels prior to the start of the game. Once the game begins, the panels shall be treated like the roof, in that they may not be moved without first notifying the umpire crew chief, who shall afford the visiting Club the right to object. The panels may be moved only once during the game, and may be moved only at the conclusion of an inning.
For all games in the postseason (Division Series, League Championship Series, World Series), the Commissioner or his designee shall make all decisions regarding roof/wall panel movement, in consultation with the home Club and the umpire crew chief. The home Club shall provide to the Baseball Operations department the name of the individual responsible for the movement of the roof/wall panels. The Commissioner or his designee shall take into account the criteria that the home Club uses during the championship season, as reflected on the Club’s filing with the MLB Baseball Operations Department.
Source: Major League Baseball
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