San Francisco 49ers star defensive lineman Nick Bosa will miss the rest of the season with a torn anterior cruciate ligament, the team confirmed Monday.

Head coach Kyle Shanahan told reporters at a conference call that Bosa will undergo season-ending surgery on his right knee.

"You don't just replace a guy like Nick," Shanahan said. "Everyone has to get better."

Bosa injured himself in the 1st half of the 49ers' victory against the Arizona Cardinals on Sunday. Television coverage of the game showed Bosa on the ground on the sideline after his injury, and later gesturing toward the stands after a visit to the medical tent with a "thumbs down" as he limped toward the locker room.

Nick Bosa #97 of the San Francisco 49ers walks to the locker room during the second quarter against the Arizo

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