Williams has played a minimal role in the offense since Kyle Orton took over at quarterback in Week 5. This is the second time this season Williams has been a healthy scratch; he was also inactive Week 6 against the New England Patriots.
With Marquise Goodwin recovered from a hamstring injury and active for the first time since Week 6, Williams did not have a spot on a 46-man game-day roster.
Meanwhile, rookie guard Cyrus Kouandjio is active for the first time this season. The second-round pick slides onto the 46-man roster in place of fellow rookie Cyril Richardson, who missed practice this week after a death in his family.
Here is a full list of Bills inactives on Sunday:
WR Marcus Easley (knee)
CB Ron Brooks (groin)
WR Mike Williams
G Cyril Richardson