Source: Vollmer has knee surgery

INDIANAPOLIS -- New England Patriots starting right tackle Sebastian Vollmer, who is one of the team's top unrestricted free agents, underwent arthroscopic knee surgery Wednesday, a source confirmed.

The surgery was considered routine, according to the source. It was not immediately clear which knee he had scoped.

Vollmer had experienced swelling in one of his knees during the 2012 season but missed only one game -- Nov. 22 against the New York Jets. His absence was notable because the game was played on a Thursday, and the short turnaround -- playing four days after a win over the Indianapolis Colts -- was too much for him to overcome.

Vollmer, wide receiver Wes Welker and cornerback Aqib Talib are the Patriots' top unrestricted free agents.

The timing of the knee scope comes two weeks before the start of free agency, which adds another layer to his status. Vollmer missed most of 2012 training camp with a back ailment and was eased into action the first two games of the season, splitting snaps with Marcus Cannon before assuming a full-time role until the knee injury knocked him out of the Jets game.

The Boston Herald reported the surgery earlier Friday.