Catcher collisions are just an experimental rule for right now, but Instant Replay is here, it’s staying, and it starts today.

The Toronto Blue Jays will play the Minnesota Twins and the Milwaukee Brewers will face the Chicago Cubs in the first two of many games to allow managers to ask for Instant Replay of certain plays. Both games will be televised on MLB.TV, and many in the baseball world will be watching to see how the new system plays out.

Everyone acknowledges that the system won’t be perfect, and it will be interesting to see if cooler heads prevail during the regular season. In Spring Training, a more relaxed “games don’t mean quite as much” atmosphere, managers will likely be focused on just getting the procedure down instead of worrying about whether a call was actually correct or not.

There won’t be any flags to throw onto the field. Instead, managers will walk onto the field and discuss first what the call in question is. While this discussion is happening, a staff member will be looking at a TV monitor in the dugout, determining if the play should be looked at closer by umpires or not. If so, a signal will be given to the manager and he will ask the umpires to review the call.

Each team gets one replay request in the first six innings of a game, with an extra one granted if the call goes in the ball club’s favor. From the seventh inning on, it is up to the discretion of the crew chief if a play can be reviewed.

Nearly every play is eligible for review. The ones that are not are balls-and-strikes, checked swings, the ‘neighborhood play,’ and ground balls over the first and third base bags. Fair/foul calls on fly balls will be reviewable, as will home run calls, tag plays, force plays, base touches, and hit-by-pitch occurrences.

The entire process for challenging a play is expected to take less than a minute and a half. The process for getting the procedure down? That could take much longer. It starts today.