Williams (thigh) didn't practice Wednesday, but did some running off to the side during the portion that was open to the media, Tim Twentyman of the Lions' official site reports.
After playing through chest and hip issues earlier in the year, Williams missed Week 8 with a thigh injury that's apparently still bothering him after on the heels of a Week 9 bye. If he can't play this Sunday in Pittsburgh, the Lions will turn to Jermar Jefferson and/or Godwin Igwebuike behind lead back D'Andre Swift.