Nick Bosa Diagnosed with Knee Tendinitis, 49ers' Shanahan Updates Return Timeline After ACL Injury

San Francisco 49ers head coach Kyle Shanahan revealed that star pass-rusher Nick Bosa is considered week-to-week with tendinitis in his right knee, per Cam Inman of the Bay Area News Group.

"Pretty normal thing with ACLs," Shanahan said Tuesday, via Inman. "Gotta be smart and be week-to-week. No concerns about it being more than that."

Bosa made just three appearances during his 2025 campaign before suffering a season-ending torn ACL in his right knee.

It marked the third torn ACL of his career, as he tore the ACL in his left knee during Week 2 of the 2020 season after suffering a partially torn right ACL as a high school senior.

Bosa previously explained that he dealt with tendinitis in his right knee following the high school injury, although the issue was addressed when he underwent his latest surgery.

"I had a little tendinitis from my high school ACL, and he cleaned that up while he [fixed] my ACL," Bosa told Sports Illustrated's Albert Breer. "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."

With tendinitis in his right knee returning, it appears as though San Francisco will take a cautious approach with his activity in training camp as well as the preseason.

Before Bosa's shortened 2025 campaign, he wrapped up a 2024 season in which he recorded 52 tackles and 24 quarterback hits to go along with nine sacks across 14 appearances. He earned the fifth Pro Bowl nod of his career.

Both Bosa and the 49ers will hope that he's able to recover in time for their season-opening clash with the Los Angeles Rams on Sept. 10.