Bills' Mario Williams Visiting Specialist
The person spoke on the condition of anonymity on Wednesday because the team had not released that information. Coach Chan Gailey was expected to provide an update later in the day.
Williams was absent from team meetings, defensive end Kyle Moore said.
The Buffalo News first reported that Williams was considering having surgery. Williams signed a six-year, $100 million contract with Buffalo in March. He's been bothered by the injury since being hurt in the final week of the preseason.
The Bills (3-4) are in their bye week, and off until playing at Houston, Williams' former team, on Nov. 4.
Source: Associated Press