When Posada was placed on the disabled list July 20, the veteran backstop said he was given two weeks by the team to decide whether he wanted to delay the surgery on the right labrum.
If Posada decided to delay the procedure, he would've likely served as a designated hitter for the rest of the season while knowing such a move might prevent him from starting the 2009 season on time.
Yankees general manager Brian Cashman said the recent acquisition of Xavier Nady gave the club a reliable hitter and took the pressure off Posada. After meeting first with Hal and Hank Steinbrenner, Cashman met with manager Joe Girardi and Posada before Monday night's series opener against Baltimore.
"I think this is also what [Posada] wants to do," Cashman said. "He said, 'I agree, 100 percent.' He was willing to do what we wanted when there was a need, so he was delaying the surgery for that need. Now that we have a hitter, I think this was predictable."
Cashman said Dr. David Altchek, based in New York, will handle the procedure, but there is no date set. The rehabilitation will take a minimum of six months, Cashman said.
After never having spent a day on the disabled list before this season, Posada's weakened shoulder made it easy for opposing clubs to take advantage of him on the basepaths. The Yankees tried a strengthening program to help his shoulder, but the repeated workload of throwing made the gains negligible.
"After speaking with Brian and Joe, we thought it was best for me -- and the team -- to have the surgery now," Posada said in a statement. "I've always taken pride in being there for my team and playing every day with them. With Xavier here, there isn't as much pressure on me to return.
"As difficult as it is, I can focus on coming back 100 percent for next season instead of coming back at less than that now."
Willie Bans is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.