Baseball begins instant replay today

Michigan

Word is they expect to get at least one disputed call per week and although they don't have a time limit they would like the process
to take no more than 2 1/2 minutes.

edmundfitzgerald

The replay booth is under the stadium at some stadiums. Only the crew chief can see the replay and make a decision to over rule a call.
If the crew chief is umpiring second base, and there is a dispute, then he will confer with the ump who made the call. They will have
a discussion, and if the crew chief decides to go to the replay, then he has to walk off the field, through the dugout, and into the replay
room. He will have an ongoing conversation with the "war room", and then return to the field with his decision.

My guess is that this whole process will take about 5-10 minutes from start to finish.