The procedure was performed in Los Angeles by Dr. Lewis Yocum, head trainer of the Los Angeles Angels of Anaheim, who said Wolf likely will miss a minimum of one year. The 28-year-old Wolf is signed with the Phillies through the 2006 season.
Yocum said Wolf is expected to begin rehabilitation in Los Angeles on July 19 shortly after a follow-up examination.
This season, Wolf was 6-4 with a 4.39 ERA in 13 starts. He was never able to throw any harder than 87 mph on the speed gun and had been on the disabled list since June 13 after a start against Milwaukee.
"It is in the best interest of my career to do this," Wolf said recently. "I can come back, get healthy and have the ability to pitch next year, which is very important."