Buffalo Bills defensive end Mark Anderson needs surgery to repair a left knee injury and could miss several weeks.
Coach Chan Gailey said the injury is not season-ending but believes Anderson will miss multiple games. General manager Buddy Nix said earlier Wednesday Anderson would miss "significant time."
Anderson, signed as a free agent in the offseason to a four-year, $27.5 million deal, has just 1.0 quarterback sack in the first five games. He had 10 sacks with the New England Patriots last season.
Anderson was injured in the second half of Buffalo's 45-3 loss at San Francisco on Sunday.