Ground Rule Double

 

A ground rule double in baseball is an award of two bases to all baserunners, including the batter-runner, as a result of the ball leaving play after being hit fairly and leaving the field under a condition of the ground rules in place at the game's location. A ground rule double occurs when a batted ball hits the ground in fair territory and lands out of play due to some distinctive feature of the grounds, most usually by bouncing over a fence or wall in the outfield.

Any baserunners ahead of the batter are entitled to advance two bases from their positions at the time of pitch when two bases are given by ground rule or league-wide rule. They may not move any further. Because a fast runner beginning from first base must halt at third base, this can sometimes deny a team a run. A sluggish runner on second base immediately scores on a ground rule double, which can be an advantage.

Home runs were previously counted on all batted balls that cleared the fence after a bounce in fair area or on a fly. The American League amended the regulation prior to the 1930 season, and the National League followed suit on December 12, 1930.