Dr. Neal ElAttrache performed an arthroscopic operation on Guerra's pitching shoulder to clean up bursitis and the acromioclavicular joint, where the top of the scapula meets the collarbone.
According to the club, Guerra will start a throwing program in six weeks and is expected to be competitive by Spring Training.
The news continues a season of injury for Guerra, who underwent right knee surgery June 5 to repair torn cartilage after being struck in the face by a line drive. When the season ended, Guerra was sidelined with a strained oblique muscle.
Guerra was the surprise of the bullpen in 2011, called up from Double-A in May and inheriting the closer job from a struggling and injured Jonathan Broxton. He saved 21 games as a rookie with a 2.31 ERA.
But even before his knee injury this season he was hit harder and more often than the previous year. In 2012, Guerra was 2-3 with a 2.60 ERA in 45 games with eight saves and five blown saves. Guerra was a fourth-round Draft pick in 2004 who overcame Tommy John elbow reconstruction in the Minor Leagues.
Guerra brings the Dodgers' surgery total this year to an unlucky 13 -- Guerra (knee and shoulder), Todd Coffey (elbow), Scott Elbert (elbow), Kenley Jansen (heart), Ted Lilly (shoulder), A.J. Ellis (knee), Mark Ellis (leg), Dee Gordon (thumb), Jerry Hairston (hip), Justin Sellers (back), Matt Kemp (shoulder) and Alfredo Silverio (elbow).
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.