NEW YORK -- If the New York Yankees are going to earn a 14th consecutive playoff berth, they'll have to do it without Jorge Posada.

The five-time All-Star catcher will have season-ending surgery on his right shoulder, ending his attempt to return to the lineup for New York's postseason push.

Posada has struggled with shoulder pain most of the season, weakening his throws and limiting his playing time behind the plate.

On the disabled list for the second time this year, Posada was trying to rehabilitate his shoulder enough to come back as a DH or first baseman this season. But after the Yankees acquired outfielder Xavier Nady in a trade with Pittsburgh on Saturday, they determined it was best for Posada to have surgery now, general manager Brian Cashman said Monday.

"It's just the obvious way to go," Cashman said.

Posada is expected to be sidelined at least six months and it's not certain that he'll be ready for the start of spring training, Cashman said.

New York announced the decision after Posada met with Cashman and manager Joe Girardi following batting practice. Cashman also spoke to co-chairmen Hank and Hal Steinbrenner to "make sure that they were all on board."