MLB experiments with DH, pitcher's mound in Atlantic League


Big changes are coming to Atlantic League baseball.

This season, the Atlantic League, an independent league separate from the minor leagues, will make changes to the pitcher's mound and the designated hitter position, with MLB keeping an eye on how things go.


Starting May 27, the Atlantic League’s Opening Day, the DH position will be tied to each team’s starting pitcher. Once a starting pitcher is removed from the game, the team will lose its DH in a move called the “double hook.” For the remainder of the game the team will either have the relief pitchers bat in the vacated spot or begin using pinch hitters.

If it works, the move could be a way to unify the rules between the American League and the National League in MLB. The Atlantic League also hopes the double hook will encourage teams to leave starting pitchers in games longer, adding value to starters who can work deeper into games. According to the League, 90% of starters were pulled before completing seven innings in 2020.


In addition, the Atlantic League will move back the pitchers mound one foot, to 61’6, starting in the second half of their season. The goal is to give batters more time to react, as pitchers’ velocities have increased over the years. According to the League, the strikeout rate in MLB has jumped from 16.4% of plate appearances in 2005 to an all-time high of 23.4% in 2020. The League says that by moving the rubber back 12 inches, batters’ reaction times to a 93.3 mph fastball will be close to the reaction time needed to hit a 91.6 mph fastball on the current mound. Further, the League says a study by the American Sports Medicine Institute shows that moving the rubber back a foot will not increase injury risk for pitchers.


If adopted in MLB, the rule change would mark the first time the mound has been moved back since 1893. However, in 1969 the height of the mound was lowered from 15 inches to 10.

This isn’t the first time MLB has used the Atlantic League as an experimental lab. In 2019, the Atlantic League was first to mandate relief pitchers to face a minimum of three batters or the end of an inning. MLB adopted that rule one year later.

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