Williams was the starting nose tackle last year but broke his leg at Seattle in Week 2 and was lost for the season. He required four surgeries, the last coming in February. Barring a setback, it is not out of the question that Williams will be ready to play Week 1 of the regular season at Dallas on Sept. 7.
The 49ers have several other players dealing with varying degrees of injuries on the defensive line. They finished their first preseason game, at Baltimore on Thursday, with four healthy defensive linemen.