MLB, Atlantic League team up for more experimental rules

Major League Baseball adopted a series of major rules changes for the 2023 season, but the experiments with other potential changes continue in the Minor Leagues and, as announced Tuesday, the independent Atlantic League.

During its 2023 season, the Atlantic League, which has served in recent years as a partner league of MLB for observations of inventive ideas, will put the following experimental rules to the test:

1. The 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.

This rule is intended to inject more speed into the sport, without a subsequent decrease in offensive upside when that spot in the batting order comes up again. MLB has never allowed players who exit a game to return to it.

2. Single disengagement limit: In conjunction with the introduction of the pitch timer, the new MLB rules restrict pitchers to two so-called disengagements (stepping off the mound or pickoff attempts) per plate appearance without penalty. On a third disengagement, the pitcher is charged with a balk, unless an out is recorded. The reason for this limit is that these disengagements reset the timer, so the limit prevents pitchers from abusing the system. The related effect is that baserunners can take more daring leads on the basepaths.

In the Atlantic League (ALPB) in 2023, pitchers will be limited to just one disengagement. The effects this restriction has on baserunning will be studied by MLB.

3. The “Double-Hook” designated hitter: Though revolutionary in general, this rule is old hat to the Atlantic League, which has used some form of it since 2021. Once again this year, ALPB clubs may use the DH as long as the starting pitcher completes 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 and must either have its pitcher hit or use pinch-hitters when that spot in the lineup comes up.

With bullpens having taken on a much more pronounced role in the modern MLB, the intent of this experiment is to monitor the impact on starters going deeper into games.

“We thank the Atlantic League for their continued partnership,” MLB vice president of baseball operations Morgan Sword said in a statement. “In recent years, the ALPB’s experimental rules have aimed to emphasize athleticism, improved pace of play and other means of giving fans the game they want to see. We are excited for another great season of Atlantic League baseball and the entertainment that it will bring to fans.”

Said Atlantic League president Rick White: “Our players and coaches are helping shape the future of the game.”

The defensive shift restrictions and bigger bases that arrived in the big leagues this year were first experimented in the Atlantic League prior to additional experimentation at the affiliated Minor League levels.

This year, the Minor Leagues are continuing to experiment with two versions of the automated ball-strike system (ABS, or the so-called “robot umps”) -- a full ABS for all ball/strike calls and a ball-strike challenge system in which teams get three challenges of an umpire’s ball/strike call per game.