Plays at the plate or on the bases will not be subject to replay review in Major League Baseball, but umpires have signed an agreement to use replay to determine home runs and whether a ball is fair or foul.

NEW YORK — Baseball umpires and management signed an agreement Wednesday that will allow the sport to start using instant replay to help determine calls on the field.

Major League Baseball still hasn't determined when the use of replays will start. Installation of equipment has been going on at ballparks, and officials have said they hoped to start using replay in August.

Replays will be limited to boundary calls, such as determining whether fly balls were fair or foul, or whether they went over fences.

"I told our members that it's just another tool that we can use to get the play right, not to look at it as a negative, but a positive," World Umpires Association president John Hirschbeck said. "As hard as you try, as much as you hustle, sometimes with just the landscape of the ballparks nowadays, it's hard to tell. So if we can get it right, you know what, let's use it as a tool to get it right."

The deal was signed by management lawyer Dan Halem and WUA attorney Brian Lam one day after a WUA spokesman went public with complaints over negotiations.

After haggling over final details, the sides exchanged proposals Tuesday night.

"We reached an agreement. Final decision with respect to moving ahead has not been made yet, but we have an agreement with the umpires," said Rob Manfred, baseball's executive vice president of labor relations.

Finalization of the agreement was first reported by murraychass.com.

"We're going to move forward with the understanding the sides will come to the table later and iron out some of the remaining issues," said WUA spokesman Lamell McMorris, who criticized management on Tuesday. "Instant replay will be a work in progress."

Umpire crew chiefs will determine when replay will be used and will make the final decisions on calls. Up to three umpires will be able to look at the replays, which will be provided from a "war room" at Major League Baseball Advanced Media in New York. It's possible as many as five umps could review the replays during postseason.

Umpire supervisors at BAM may speak with the technicians but will not confer with the umpires about the calls, Hirschbeck said.

"They'll be some form of training," McMorris said. "We'll have to figure out how."