A MRI confirmed the 49ers’ worst fears: Jimmy Garoppolo is out for the season with a torn ACL.

The team announced the news Monday afternoon, one day after 49ers coach Kyle Shanahan said the team anticipated its quarterback had suffered the injury.

Garoppolo hobbled off the field during Sunday’s loss to the Chiefs after he scrambled out of the pocket and ran on a third-and-goal play. It appeared Garoppolo tried to stay in bounds instead of stepping out, and his left leg buckled as he absorbed a hit from a Chiefs defender.

Shanahan said the 49ers will turn to C.J. Beathard as their starting quarterback. Beathard completed 123 of 224 passes for 1,430 yards and four touchdowns with six interceptions as a rookie last season, going 1-4 in five starts.

Nick Mullens, a second-year pro out of Southern Miss, is on the 49ers’ practice squad and presumably will be called up to back up Beathard. Mullen hasn’t played in an NFL regular-season game, though he did complete 31 of 43 passes for 396 yards with one touchdown and three interceptions in four preseason contests this year.

The 49ers now will play on without two of their biggest offensive weapons, as running Jerick McKinnon tore his right ACL during the preseason and also is out for the season.


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