MLB's Atlantic League to Test Experimental Rules, Including Designated Pinch Runner.
Major League Baseball will test three experimental rules in the Atlantic League this season, including the use of a designated pinch runner who is not in the starting lineup, a limit of one disengagement from the pitching rubber per at-bat, and the "Double-Hook" designated hitter rule. The rules will go into effect on April 28, and are aimed at emphasizing athleticism, improving pace of play, and incentivizing speed.