San Francisco 49ers general manager John Lynch says quarterback Jimmy Garoppolo is "heartbroken" over his ACL tear incurred in Sunday's loss to Kansas City, but Chiefs linebacker Justin Houston puts the blame squarely on the shoulders of Garoppolo himself.

"That was his fault,” Houston said of the injury that occurred in the fourth quarter of the 38-27 Chiefs victory. “... As a quarterback you should step out of bounds. It was only an inch. That inch wouldn’t have made a difference. You got the yardage you need, you step out of bounds. You got to be smart.”

Garoppolo was scrambling for additional yardage on a late drive when the injury occurred. The 26-year-old pivot had the opportunity to step out of bounds, as he was near the sideline, but his leg appeared to get caught in the turf before Garoppolo took a hard hit from Chiefs cornerback Steven Nelson.

Garoppolo joins a lengthy Niners injury list. Cornerback Richard Sherman left the game with a calf injury, while his replacement Jaquiski Tartt also exited early with an apparent wrist injury.

“Any time you lose your starting quarterback, that’s a big deal," said head coach Kyle Shanahan. "It was when we lost our starting running back [Jerick McKinnon, to a torn ACL in preseason], too. Feel for him personally. I know how disappointed he is."

Backup quarterback C.J. Beathard will get the start in Week 4 against the Los Angeles Chargers. Practice squad member Nick Mullen is the only other QB currently on the Niners' roster.

Garoppolo wasn't the only Niner to pick up an injury on Sunday. Cornerback Richard Sherman left the game with a calf injury, while his replacement Jaquiski Tartt also exited early with an apparent wrist injury.

The Niners (1-2) sit two games back of the undefeated Los Angeles Rams (3-0) in the NFC West.