Getty Images

Major League Baseball announced on Tuesday that three new rules experiments will be tested during the upcoming season in the independent Atlantic League, with which MLB has a partnership. 

The Atlantic League season gets underway on April 28, and during the season they'll test new rules involving designated pinch runners, the "double hook" DH rule, and further limitations on mound visits. Here's how MLB in a joint release with the Atlantic League explained those experimental rules: 

  • New to the Atlantic League this season will be the use of a Designated Pinch Runner. Each club will list a player who is not otherwise in the starting lineup as a designated pinch runner. That player may then be substituted at any point into the game as a baserunner. The player who is substituted for, as well as the pinch runner, may then return to the game without penalty.
  • Unlike the new MLB rule which allows a pitcher to disengage from the pitching rubber twice during an at-bat, the Atlantic League test will permit only a single disengagement per at-bat in 2023.
  • The ALPB will continue the use of the "Double-Hook" DH rule, which allows clubs to use the designated hitter throughout the game provided that the club's starting pitcher has completed at least five innings. If the starter fails to make it through the fifth, the club then loses the DH for the remainder of the game.

MLB continues to be in the mood for experimentation under commissioner Rob Manfred, particularly after the new suite of rules at the MLB level -- including, most notably, the use of a pitch clock -- have thus far proved successful when it comes to their stated purposes. 

MLB has previously used the Atlantic League as a rules laboratory of sorts. As the release notes, the Atlantic League has previously been host to trial runs for rules considerations like automated ball-strike calls, larger bases, an expansion of the distance between home plate and pitching rubber, and allowing the batter to advance to first base on any pitch not caught in flight by the catcher. CBS Sports' R.J. Anderson took a deeper look at the experiments and their impact on Atlantic League players in 2021

The typical path for rules that prove successful in the Atlantic League is for MLB to then test them in the affiliated minor leagues before considering them for use at the big-league level.