The Chicago Tribune reported the operation was to correct a problem first detected during a postseason physical.
The exact nature of the injury has not been disclosed, but a source told the newspaper that the procedure was performed on Urlacher's lower neck region and focused on the cervical curve of the spine.
The eight-year veteran was not selected for this season's Pro Bowl for the first time in his career, despite finishing with a team-high 158 tackles and his first interception for a touchdown.
The former New Mexico product was the league's first player ever with five sacks and five interceptions in the same season.
The Bears had no comment on the surgery, but the report added that the injury wasn't believed to be serious enough to keep him off the field if the Bears had made the playoffs.
Urlacher is expected to make a full recovery and be 100 percent healthy by training camp next July.