49ers' Mykel Williams: practicing, but not eligible yet

San Francisco opened Mykel Williams' practice window on Wednesday, September 30. It gives the defensive lineman a path back after last season's torn ACL.

Williams remains on the physically unable to perform list. He cannot play against Denver in Week 4, even though he has returned to practice.

A 2026 rule change allows reserve/PUP players to start their 21-day practice window after their team's second regular-season game. They must still miss the first four games before activation.

The window lets San Francisco evaluate Williams without immediately moving him to the active roster. To return this season, he must be activated before that window expires.

Williams was limited in Thursday's practice for a second consecutive session. A practice participation level describes that session; it is not a new game-status designation.

Week 5 against Seattle is Williams' earliest possible appearance. That is an eligibility limit, not a promise that he will be ready. Returning to games still requires an activation decision.