While the Cincinnati Bengals hold out some hope that Madieu Williams might be able to return late in the season or for the playoffs, the team faces the prospect of playing the rest of the year without the starting free safety, who earlier this week underwent surgery to repair a torn labrum in his left shoulder. Coach Marvin Lewis confirmed the procedure but declined to speculate about how long the rehabilitation period might be. There is a good chance, though, that the labrum surgery will be season-ending, which would mean that the Bengals, contending for their first division title since 1990, would be without both starting safeties from a year ago. Veteran safety Kim Herring sustained a shoulder injury in the preseason and was placed on injured reserve even before the start of the campaign. It is believed that Williams, one of the league's outstanding defensive rookies in 2004, suffered the labrum injury during a non-contact drill in a Sept. 30 practice.