"[Head athletic trainer] Richie Bancells told me it wasn't as bad as they originally had thought," Trembley said.
Hill revealed on July 29 that he had been pitching with a torn labrum in his throwing shoulder, which was diagnosed before he was traded to the Orioles. He was placed on the 15-day disabled list and was scheduled to see an orthopedic specialist to determine if surgery was necessary or if a strengthening program for the muscles around the labrum would be enough.
"He had surgery yesterday from Dr. [Lewis] Yocum in Los Angeles," Trembley said Saturday.
The manager expects Hill to be ready to throw again by Spring Training 2010.
Trembley also updated the status of right-hander Brad Bergesen, who went on the DL on July 31, a day after he was struck in the left shin by a line drive.
Trembley said Bergesen will be re-evaluated on Monday and will begin a throwing program when he stops limping.
Erika Gilbert is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.