Overview

• Bosa’s right leg appeared to buckle on a first‑quarter rush, after which he entered the blue tent, briefly tested the knee on the sideline, gave a thumbs‑down gesture, and walked to the locker room.
• San Francisco first listed him as questionable to return before ruling him out at halftime.
• Coach Kyle Shanahan said sideline tests did not indicate an ACL tear, but he noted concern based on how Bosa felt and said an MRI is scheduled.
• The injury lands as the 49ers manage other key absences, and Bosa’s history includes a 2020 ACL/MCL tear in his left knee.
• Before exiting, Bosa recorded two tackles; he had opened the season with a sack in each of the first two games as the 49ers edged Arizona 16–15.