what is the rule for challenges in mlb
Instant replay in Major League Baseball The current instant replay system was implemented in the 2014 season. Under the current system each manager is allotted one challenge per game, with additional challenges granted only if the previous one was successful. From the eighth inning on, the umpire crew chief is allowed to initiate his own replay review. The umpire crew chief is also allowed to initiate a review during any inning if the play in question is a boundary home run call.