That would leave the Steelers, who already have Le'Veon Bell on injured reserve, down to Fitzgerald Toussaint and Jordan Todman at running back.
NFL Media's Ian Rapoport reported, per a source, that the Steelers consider Williams out with the foot injury. If Pittsburgh wins in Cincinnati on Saturday, there is a chance Williams could play in the divisional round.
Williams finished the regular season with 907 rushing yards and 11 touchdowns on 200 carries. He injured his right foot in the first half against the Cleveland Browns last Sunday.
Toussaint replaced Williams in the game and ran for 24 yards on 12 carries.