The San Francisco 49ers are 3-0 despite dealing with injuries to key roster pieces, and are alone in first place in the NFC West. But yet another star player left Sunday’s game against the Arizona Cardinals, and it is unclear just how serious Nick Bosa’s injury is.
49ers Lose Nick Bosa During Game Against Cardinals
Late in the first quarter of the 49ers win against the Cardinals, Bosa departed the game after being knocked to the ground on a pass rush. He appeared to tweak his knee on the play, and then walked slowly to the sideline.
After a visit to the blue medical tent, Bosa attempted to stretch on San Francisco’s sideline. He eventually made his way to the locker room and never re-entered the game.
49ers HC Kyle Shanahan told reporters that they believe Nick Bosa avoided an ACL injury, but the team needs to do further tests to determine the extent of the knee injury.
— Adam Schefter (@AdamSchefter) September 21, 2025
There was of course immediate concern for the former Defensive Player of the Year. Speculation of an ACL injury was the general thought in the media and on social media, but Nick Bosa may have avoided the worst.
After the game, 49ers head coach Kyle Shanahan said that the team believes that Bosa had avoided an ACL ailment, but that further tests would need to be done to determine the severity of the injury.
San Francisco Dealing With A Serious Injury Bug
If he misses any extended period of time, it would be just the latest event in a string of bad luck for San Francisco. The team entered the season short at the wide receiver position, with Brandon Aiyuk out and Jauan Jennings in and out of the lineup.
#49ers edge Nick Bosa is getting tests on his knee injury, coach Kyle Shanahan said. While the team does not believe it’s an ACL injury, they are checking everything. pic.twitter.com/MQg8TAaN0d
— Ian Rapoport (@RapSheet) September 21, 2025
Things got worse in Week 1 when they lost tight end George Kittle to a hamstring injury, and newly paid starting quarterback Brock Purdy hasn’t played since the opening weekend.
The only saving grace for the 49ers is their schedule. They have one of the softest collection of opponents of any team in recent memory, and plenty of winnable games still coming up this season. But after they take on the Jaguars in Week 4, they’ll be on the road for four of the next five games, including a contest against the Tampa Bay Buccaneers on October 12th.
