A manager or coach can make one mound visit per pitcher per inning without needing to remove the pitcher from the game. If a manager or coach visits the same pitcher twice in one inning, the pitcher must be removed from the contest.
Mound visits are limited to 30 seconds, starting when the manager or coach has exited the dugout and been granted time by the umpire.
The mound visit is considered to be concluded once the manager or coach leaves the 18-foot circle surrounding the pitching rubber, though they are permitted to temporarily leave that area to notify the umpire of a substitution. The manager or coach can then return to the mound without it being counted as two mound visits. At the discretion of the umpire, a manager or coach may be permitted to visit a pitcher to check on a potential injury without the trip being counted as an official mound visit.
History of the rule
Mound visits had no time limit prior to the 2016 season, when Major League Baseball began limiting visits to 30 seconds.
Watch: Astros manager A.J. Hinch makes a mound visit in the ninth inning to talk to Lance McCullers.