Nick Bosa leaves field with knee injury as 49ers face layered injury woes

San Francisco 49ers outside linebacker Nick Bosa left Sunday’s game against the Arizona Cardinals with a knee injury in the first quarter, signaling trouble with a thumbs-down gesture as he walked off the field. The 49ers ruled him out for the remainder of the game, marking another setback for a team already dealing with a spate of injuries early in the season.

Bosa’s injury occurred on a pass rush attempt as he chased Cardinals quarterback Kyler Murray. Two Arizona linemen pushed away from the passer and to the ground, and Bosa appeared to land awkwardly. He was attended to on the sideline before being ruled out, and there was no immediate public update on a potential return timeline. The absence added to a list of missing players that already included several key contributors for San Francisco this week.

The larger context for the 49ers includes quarterback Brock Purdy’s ongoing absence with a sprained left shoulder and turf toe, wide receiver Jauan Jennings sidelined with shoulder and ankle injuries, and tight end George Kittle out since Week 1 with a hamstring issue. Bosa’s early exit underscored San Francisco’s vulnerability on both sides of the ball as it tried to navigate the scoreboard without several of its usual contributors.

Bosa, 27, has established himself as one of the league’s premier pass rushers since being drafted in 2019. Through his NFL career, he has accumulated 64.5 sacks, ranking fourth in the league over that span behind only T.J. Watt, Myles Garrett and Trey Hendrickson. He entered the 2025 season with two sacks already this year before injuring himself in Week 3, a reminder of the high impact he provides when healthy.

Off the field, Bosa has drawn public attention for political gestures. He earned praise from former President Donald Trump last year after celebrating a sack with the president’s signature dance, and Trump wrote about him on Truth Social. The endorsement, however, came amid controversy when the NFL fined him $11,255 for displaying political messaging on another occasion. The interplay between Bosa’s performance on the field and his public profile has remained a talking point among fans and analysts alike, even as he has continued to produce at an elite level when available.

The injury comes at a season in which San Francisco has aimed to maintain a high level of performance while managing the absence of key players. The club will likely update Bosa’s status in the days ahead as medical staff evaluate the knee and determine a return plan, though no timetable was provided in the immediate aftermath. In the meantime, the 49ers will rely on depth along the edge as they navigate a schedule that tests the durability of one of the league’s strongest defenses.

For fans and analysts, the question now centers on the timeline for Bosa’s return and how the defense will compensate if he misses more time. The 49ers have shown resilience in past seasons when injuries have thinned the lineup, but Week 3’s development adds to a growing list of concerns as the team seeks to sustain momentum early in the campaign.