The 49ers received devastating news on Monday morning.

Defensive end Nick Bosa, who left Sunday's 16-15 win over the Arizona Cardinals with a right knee injury and did not return, suffered a season-ending torn ACL, ESPN's Adam Schefter reported Monday, citing sources.

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Bosa left the game in the first quarter and immediately went to the blue medical tent, where he eventually reappeared and gave a thumbs-down sign, which was an early indication that the injury could be serious.

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San Francisco coach Kyle Shanahan stated after the game that the team was hopeful it was not an ACL injury for Bosa after the initial assessment on the sideline, but later clarified tha

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