Major League Baseball and the World Umpires Association appear close to an agreement on a new contract, baseball sources said on Monday.

The deal, which expires on Dec. 31, has been in negotiation all year and could be announced sometime in the next few days. A baseball official said on Monday that a deal isn't done and no announcement is planned yet for Tuesday.

MLB is seeking more flexibility in assigning umpires during the postseason, plus more flexibility in expanding instant replay.

As of now, umpires can't work in consecutive postseason series. The crews that work the two League Championship Series can't work in the World Series.

As far as replay is concerned, it now covers boundary calls on home runs -- fair or foul, in or out. That issue was negotiated with umpires outside of regular collective bargaining in 2008 and the program was put in place in August of that year.

Commissioner Bud Selig said recently that he would consider expanding replay after a spate of missed calls plagued the postseason.