Coach Mike Tomlin said Tuesday that Williams is ''day to day'' after injuring his right leg in last weekend's victory over Cleveland.
The 32-year-old Williams tied for the NFL lead with 11 rushing touchdowns while filling in for Le'Veon Bell, who is out for the season with a torn ligament in his right knee.
If Williams can't play, the Steelers will rely heavily on Jordan Todman and Fitzgerald Toussaint as they prepare for the AFC North champion Bengals. Toussaint ran for 24 yards on 12 carries against the Browns and also caught a 2-point conversion. Todman has four carries for 22 yards in limited playing time this season.
AP NFL website: www.pro32.ap.org and http://twitter.com/AP-NFL