Williams is dealing with AC sprain that occurred on a diving catch attempt during practice, Alan Saunders of SteelersNow.com reports.
Steelers head coach Mike Tomlin indicated Saturday that Williams will be out for "days," so the tight end could miss numerous practices and may not be ready for Pittsburgh's first preseason contest Aug. 9 versus Houston. Williams got into 13 regular-season contests with the Steelers last year but didn't log any catches and played primarily on special teams.