The team is awaiting the results of an MRI exam, but the NFL Network reported Saturday morning that the injury did not involve Williams' ACL.
Williams was hurt during a running play but was able to limp off the field. He left the stadium wearing a full-length brace on his leg, according to Pro Football Talk. He had one tackle in the contest, a 19-17 win for the Bills.
The 35-year-old has been a mainstay on the defensive line for Buffalo since the team drafted him in the fifth round of the 2006 NFL Draft out of LSU.
Williams started all 16 games in 2017, the sixth time in his 12 NFL seasons with the Bills that he has started every game. He had 41 tackles and three sacks while playing both tackle positions.
The 6-foot-1, 305-pounder has collected 43.5 sacks in 167 regular-season games (162 starts) with Buffalo.
A five-time Pro Bowl selection, Williams established a career high with 10.5 sacks with 10.5 sacks in 2013. He has started at least 14 games in nine of his 12 seasons.