What happened: The issue is in the ACL-repaired knee that ended Bosa's 2025 season after three games. Shanahan called tendinitis a normal occurrence in ACL recoveries and said the team must manage it carefully.
Why it matters: The 49ers previously kept Bosa off the PUP list as he worked toward the opener. His new status puts the focus on how much preparation time he gets before Week 1.
By the numbers: Bosa recorded 17 tackles, two sacks and two forced fumbles across three games in 2025.
What to watch: His practice participation will show whether the knee responds to reduced work. Week 1 availability remains the key checkpoint.