Atlantic League to move mound back for MLB experiment

The pitching rubber will be bounced back a bit this summer in an experiment at the minor league level that will be implemented in conjunction with Major League Baseball.

Instead of the regular 60 feet, 6 inches between the top of the mound and home plate, as is standard from high school play up through professional baseball, MLB will ask the independent Atlantic League to move its mound back to 61 feet, 6 inches.

The change will be made only for the second half of the season with data being compared against data from the first half when the mound will be at the regular distance.

In another experiment, Atlantic League managers will have to consider a “Double-Hook” rule where a team would lose its designated hitter once the starting pitcher is removed from the game. Relief pitchers or pinch hitters would then hit in the spot for the remainder of the game.

MLB has used the Atlantic League to test new rules concepts, including an electronic system to call balls and strikes.

The Atlantic League was the first to use the three-batter-minimum rule for relief pitchers that is now in use at the MLB level. It has also tested larger 18-inch bases, as well as defensive positioning restrictions, both of which will be used in affiliated minor league play this season.

The goal of moving back the mound ever so slightly would be to assist the overall offensive flow of the game. Strikeouts have gone up in every season since 2005 as velocity has increased. According to MLB data, the strikeout rate was 16.4 percent in 2005 and is 24.9 percent through the first few weeks of the 2021 season.

The mound has been at 60 feet, 6 inches from home plate since 1893, when it was moved back from 55-feet, 6 inches. Data from that era showed that strikeouts declined 3.3 percent, while batting average rose from .245 to .280.

The “Double-Hook” rule would give managers incentive to leave starters in games longer. According to, identifiable starters, considered “workhorses” that fans identify with, are good for the sport.