NEW YORK -- Yankees catcher Jorge Posada underwent arthroscopic surgery Wednesday on his injured right shoulder in Manhattan. The procedure was performed by Dr. David Altchek, and Posada will begin a rehabilitation program in four to six weeks.

The Yankees decided Monday that Posada would have the surgery after he unsuccessfully tried to come back from the disabled list. He went on the DL on July 20.

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. He was also on the DL from April 28 to June 3 with a strained right shoulder that was later diagnosed as right rotator cuff tendinitis.

Posada batted .268 with three home runs and 18 RBIs this season. Before he was placed on the DL in July, Posada was mainly a designated hitter and first baseman, with Jose Molina assuming regular catching duties.