San Francisco 49ers pass rusher Nick Bosa is expected to miss multiple weeks due to a calf strain suffered during a team warmup. The injury adds to severe defensive line attrition for the team ahead of a Week 3 matchup against the Arizona Cardinals.
Warmup Injury Sidelines All-Pro Pass Rusher
The San Francisco 49ers’ defensive front lost its most prominent anchor when pass rusher Nick Bosa pulled his calf during a high-knees warm-up before a walkthrough practice. Head coach Kyle Shanahan addressed the unexpected development, explaining that the injury occurred right before team preparations.
“Just his warmup deal. Right before walk-through he does his own warmup there on the side and just got his calf doing it.”
Kyle Shanahan, Head Coach, via Yahoo Sports
While initial reports from league insiders pointed to an absence of several weeks, the team has not yet decided whether to place the five-time Pro Bowler on injured reserve, which would require a minimum four-game absence. Shanahan noted that management is weighing that exact roster status.
Mounting Attrition Along the Defensive Front
Bosa’s absence compounds a staggering run of injuries for San Francisco’s defensive line. Defensive tackle Osa Odighizuwa described the mounting losses as a “horror show” following a three-week span that decimated the team’s depth chart.
Entering a Week 3 contest against the Arizona Cardinals at Levi’s Stadium, the 49ers are managing a heavily depleted roster up front. The team opened the season with nine defensive linemen on the 53-man roster, but only three remain available to play: Odighizuwa, Keion White, and rookie fourth-round pick Gracen Halton.
- Sam Okuayinonu suffered a broken foot.
- Alfred Collins sustained a torn patellar tendon.
- CJ West landed on injured reserve with a chipped knee bone.
- James Thompson Jr. dealt with a high ankle sprain.
- Romello Height underwent surgery for a broken hand.
Previous Medical Setbacks and Roster Adjustments
The latest lower-body injury adds to a medical file that includes three torn anterior cruciate ligaments across Bosa’s career, including a tear in his right knee during Week 3 of the 2025 season against Arizona. Bosa also missed nearly a month of training camp this year due to tendinitis in the same surgically repaired knee before returning for the team’s first two games on a pitch count.
To navigate the shortage, San Francisco has actively scanned the market. General manager John Lynch noted that the team previously reached out to free-agent pass rushers, including Leonard Floyd, after losing Okuayinonu just before the season opener. Meanwhile, the franchise has pulled depth pieces from practice squads, promoting veterans like Ogbo Okoronkwo and signing players such as Naquan Jones.
Decisions Facing the Coaching Staff
With Bosa sidelined for multiple weeks, the 49ers must balance the urgency of an 18-week season against the risk of rushing their star pass rusher back too quickly.
Whether the team elects to place Bosa on injured reserve depends heavily on available roster spots, as league rules limit teams to eight player returns from the list. As San Francisco prepares to host Arizona, the immediate focus shifts to White, Kareem, and newly elevated reserves to hold the line.