PHOENIX -- Major League Baseball isn't done tinkering with potential rule changes for the sport.

The league announced a series of experimental rules Tuesday that will be used in the Atlantic League this season, including a designated pinch runner, "double-hook" designated hitter rule and further limitations on a pitcher's ability to make pickoff moves.

The designated pinch runner rule allows a player who is not in the starting lineup to be used at any point of the game as a substitute baserunner. The player who was subbed out, as well as the pinch runner, would still be able to return to the game.

The "double-hook" designated hitter rule allows teams to use the DH throughout the game as long as the starting pitcher throws at least five innings. If that doesn't occur, then the team loses its DH and the pitcher's spot would bat for the remainder of the game. The rule was also used in the Atlantic League last season.

There's also a single disengagement rule, which means pitchers can only take their foot off the rubber once per at-bat to attempt a pickoff or reset the pitch clock.

The Atlantic League is an independent minor league that has been a designated MLB Partner League since 2019, helping the sport test new rules. Some of the rules have stuck and eventually been used in the big leagues, while others haven't.

MLB has debuted a series of rules changes this season that were tested throughout the minors, including the Atlantic League. The new pitch clock has shaved about 30 minutes off game times through the season's first three weeks, while limits on the infield shift and bigger bases have helped boost offense.

"We thank the Atlantic League for their continued partnership," said Morgan Sword, MLB's vice president of baseball operations, 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."