Nick Bosa, star pass rusher of the San Francisco 49ers, has tendonitis in his right knee and his status for Week 1 against the Los Angeles Rams is in doubt. Bosa, who has five sacks against the Rams in 10 career games, tore his ACL in 2025 and missed all but three contests. However, it is now tendonitis in the same knee that could cause his absence to extend into the 2026 season.
#49ers DE Nick Bosa, who is returning from a torn ACL, is now considered week-to-week due to tendinitis in his surgically repaired knee, per HC Kyle Shanahan. pic.twitter.com/ktLwJ2ILOz
— Ari Meirov (@MySportsUpdate) August 11, 2026
Although George Kittle is on track to play against the Rams after tearing his Achilles in the playoffs, a remarkable recovery turnaround, Bosa’s setback is another in a long line of injury problems for the 49ers.
Bosa has a history of ACL issues
This is the third time Bosa has torn an ACL. He tore his right ACL in high school, his left ACL in 2020, and his right ACL again last year in Week 3 against the Arizona Cardinals. While this tear was being repaired, his doctor also addressed some tendonitis from the high school injury. Bosa had high hopes after that, as he explains to Albert Breer in a recent interview:
“I had a little tendinitis from my high school ACL, and he cleaned that up while he [fixed] my ACL,” Bosa explained. “That’s gone. So it’s like an improvement. So once I’m through this rehab, I feel like my right knee—because that was kind of a chronic issue that I had a little bit, and he cleaned that up in my quad tendon and that hasn’t been an issue at all—could feel better when I’m done with this recovery.”
As that interview took place only 10 days ago and Bosa had no known issues with his knee up until that point, this must have been quite concerning to Bosa and Shanahan when it flared up. Shanahan is downplaying any worries, saying it’s a normal thing for an ACL repair and they’ll be looking at it week by week.
Week 1 is only four weeks away
Will Bosa be healthy enough to fly to Australia to face the Rams? Even if he does, will the inability to work out and the lack of practice mean he’s less than 100%?
Interestingly, many of San Francisco’s backups are also hurt.
As the depth chart stands, the 49ers have Sam Okuayinonu (ankle issue) behind Bosa, as well as former Ram Ogbo Okoronkwo and rookie third-round pick Romello Height (elbow). Opposite of Bosa would be second-year man Mykel Williams (ACL), but he is also injured, as he’s on PUP and not practicing,. Behind him is Keion White, whose been dealing with a groin injury.
Shanahan and Bosa know better than anybody that the Niners’ defense revolves around Bosa. As he goes, so goes the pass rush. If there’s a chance that playing in the game exacerbates the problem, further affecting him this year, will he sit out an extra week?
I can’t imagine any Rams fans being disappointed if he does.