The wiki doesn't mention any knee tendinitis for Nick Bosa — that's not listed as one of his current issues. His 2026 season concern is a right ACL tear from September 2025 (his third career ACL tear).
That said, the news is good: as of mid-July, Bosa is on track for the 49ers' Week 1 opener in Australia on September 10. He's doing field work at OTAs, his recovery is on schedule, and the ACL tear was clean with no meniscus damage (from the Nick Bosa page). So yes, he's expected to play this season — but the injury to monitor is his ACL rehab, not tendinitis.