What happened: The designation rules him out for at least the first four games of the 2026 season. Mykel Williams had remained on active/PUP during training camp while recovering from an ACL injury.

Why it matters: San Francisco will open the season without a former first-round pick in its defensive-line rotation. Reserve/PUP prevents Williams from returning to game action before Week 5.

What to watch: Williams' rehabilitation and eventual return to practice are the next markers to watch.