Williams didn't practice Wednesday due to a rib injury.
The injury might initially seem to explain why Williams only logged three offensive snaps in Sunday's 19-17 win over the Chargers, but he actually played 13 snaps on special teams. With Jay Ajayi (knee) operating as an every-down workhorse, there simply isn't much room for Williams or Kenyan Drake to contribute. Ajayi also missed Wednesday's practice, but there's been no suggestion his injury is serious.