Buffalo Bills defensive end Mario Williams had surgery on his left wrist, the team announced Wednesday. Williams missed practice and didn't attend team meetings Wednesday while visiting a specialist to determine what to do about his nagging wrist injury. "The update on Mario is he had a procedure done to relieve some discomfort in his wrist and we expect him back for practice next week," coach Chan Gailey told the team's web site. "That's all I know at this point." Williams signed a six-year, $100 million contract with Buffalo in March, and was hurt during the final week of the preseason. The Bills (3-4) are off Sunday, then return Nov. 4 to play at Houston, Williams' former team. It's unclear whether Williams will be healthy enough to return for that game. The Bills defense ranks last against the run, and has allowed a combined 937 yards rushing over the past four games.