Boston Red Sox relief pitcher Keith Foulke underwent arthroscopic surgery on his right knee Thursday. Foulke, who is already out for the remainder of the playoffs, last pitched on September 18 in a game versus Oakland. The procedure, performed by Red Sox Medical Director Dr. Thomas Gill at Massachusetts General Hospital, was done to address the cartilage in the knee. The Red Sox indicated that Foulke will start a rehabilitation program immediately and should be ready for the start of spring training. Foulke had 32 saves with a 2.17 earned run average last year and was a key contributor to Boston's 2004 world championship run, but he hadn't come close to approaching those numbers this season. His ERA had ballooned to 5.91 and he served up eight home runs in 45 2/3 innings of work while blowing four of his 19 save opportunities for the year. He went 5-5 with 15 saves this season.