49ers HC Kyle Shanahan Reveals the Truth About Nick Bosa's Injury

It's not simply "soreness" as the 49ers initially claimed with Nick Bosa.

Jul 24, 2025; Santa Clara, CA, USA; San Francisco 49ers defensive end Nick Bosa (97) awaits his turn during pass rushing drills during the second day of training camp. Mandatory Credit: D. Ross Cameron-Imagn Images | IMAGN IMAGES via Reuters Connect

There was always something fishy about Nick Bosa missing 49ers practice for over a week with "soreness." That's not a diagnosis that typically keeps a player out for so long.

It turns out that Bosa has more than just soreness, which is what I suspected in a previous article. On Tuesday, Kyle Shanahan revealed the truth about Bosa's injury.

"Tendinitis. It's a pretty normal thing with ACLs," Shanahan said. "It's a normal thing. That's why we've got to be smart here for week to week. No concerns about him, it being more than that."

Well, that's interesting. If it was always tendinitis and it wasn't a concern, why conceal it? If it's so "normal," why is it initially being downplayed?

The 49ers treat injuries to players like a secret formula. Shanahan could've said this from the beginning and it wouldn't have been suspicision.

But now that Bosa has missed a couple more practices since he last spoke, he knows the 49ers can no longer downplay it or keep it hidden.

Bosa is week-to-week, but for how long?

Aug 3, 2026; San Francisco, CA, USA; San Francisco 49ers defensive end Nick Bosa (97) during training camp at Levi's Stadium. Mandatory Credit: Sergio Estrada-Imagn Images | IMAGN IMAGES via Reuters Connect

So, Bosa is week-to-week with tendinitis in his surgically repaired knee, but it's normal. If it's tendinitis and his knee is potentially swollen, this could be an issue throughout the season.

Bosa could play one game, then all of a sudden his tendinitis flares up for a week, keeping him out of the next game. It's a tricky scenario because of how unpredictable it is.

That means the 49ers can't count on Bosa to play all 17 games. He made it through six practices before his knee gave him issues.

How on earth is he going to play for most of a season? It feels like Bosa is more likely to play in seven games than 17. That's how concerning this is.

On one end, it's awesome that he didn't suffer anything significant. On the other end, this does carry some significance if it leads to him missing a handful of games or being limited.

Time will tell how this works out for Bosa and the 49ers. One thing is for sure: they need him out there every game. Their pass rush is irrelevant without him.

Rookie Romello Height can't be their top option on the edge. He'll only be effective when Bosa is on the field, which means everything is reliant on Bosa.

The 49ers better hope their secondary plays well this year because that is where the strength of their defense will be.

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