Williams likely sprained his knee during Thursday's win over the Bears and is expected to miss some time, although he still needs additional testing to confirm the diagnosis, Ian Rapoport of NFL Network reports.
The severity of the sprain remains unclear, but Williams' status heading into Week 5 against the Cowboys is looking bleak, even with the extra rest he'll get. Starting rusher Ty Montgomery sustained a chest injury in Thursday's game, and his status is currently unknown; if neither Montgomery nor Williams can recover in time, the Packers may be forced into utilizing Aaron Jones and Devante Mays more than expected against the Cowboys.