Baseball managers will have the right to challenge controversial calls beginning this season, the 30 major-league teams unanimously decided on Thursday, and an umpire watching replays in New York will decide whether to uphold them.

Managers will be allowed to challenge one call per game, under rules agreed to by MLB's 30 owners, and will be granted a second challenge if their first is upheld. But no manager will be allowed more than two challenges in a game, and arguing over a replay official's ruling will not be allowed.

It's a major expansion of replay in Major League Baseball, a sport which had limited the technology to home run calls until now. The new system will be tested during several exhibition games this spring, then go into effect on Opening Day.

Balls and strikes cannot be challenged, but virtually all other controversial calls can, including tag plays, trap plays, force plays, fair/foul calls in the outfield, whether batters were hit by a pitch, tag-up timing, touching of bases, passing runners, home runs and ground-rule doubles. The rule specifically creates an exception for the so-called "neighborhood play," a force at second base during a double play, which will not be reviewable.

MLB has created a "command center" in New York where major-league umpires will be stationed, with access to replays from all stadium cameras, including some not shown on TV broadcasts. When a play is challenged, the crew chief on the field will contact the replay official, using a headset on the field, and the official will determine whether the call was correct and, if the call was overturned, where baserunners should be appropriately placed.

If a manager has already used his challenge, umpires can instituted a replay review on their own, from the seventh inning on.

Teams will be allowed to station someone in the clubhouse to watch the game on TV, and communicate with the manager on whether to challenge a call. No TVs will be allowed in dugouts.

One other effect of the new rule: MLB has ended its policy of preventing replays of close plays from being shown on stadium scoreboards. Teams can now show any replay.

Here's at complete list of the new replay policies.