Williams had been added to Friday's injury report as questionable after tweaking his back getting out of bed.
The team's most tenured player is coming off his best game of the season, when he had two sacks and forced a fumble against the New York Jets.
With Williams active, all seven of the Bills' inactives are healthy scratches:
QB Jeff Tuel
RB Ronnie Wingo
LB Ty Powell
OL J.J. Unga
TE Chris Gragg