SANTA CLARA, Calif. _ Jimmy Garoppolo's season indeed is over, as a MRI exam Monday confirmed he tore the anterior cruciate ligament in his left knee late in the 49ers' loss Sunday at Kansas City.
C.J. Beathard, who went 1-4 last season as a rookie starter, will now replace Garoppolo as the injury-laden 49ers (1-2) next face the Los Angeles Chargers (1-2) on Sunday in Carson, Calif.
Garoppolo's knee buckled as he scrambled down the left sideline with 5:27 remaining in the 38-27 defeat. Sacked on the two previous plays, he was flushed from the pocket on third-and-goal and raced 13 yards to the 7-yard line, where, rather than voluntarily go out of bounds, he endured a helmet-to-helmet hit by Chiefs cornerback Steven Nelson.
So ended Garoppolo's fifth NFL season. Traded to the 49ers last Oct. 30 after a 3 {-season tenure with the New England Patriots, he went 5-0 as their December starter, prompting the 49ers to sign him on Feb. 8 to what then was the richest contract in NFL history (five years, $137.5 million).
Garoppolo not only elevated his teammates' on-field capabilities, he revitalized a frustrated fan base, so much so that the 49ers gave out Garoppolo bobblehead dolls at last week's home-opening win over the Detroit Lions.
Beathard served as the go-between starter last season, taking over from Brian Hoyer after an 0-4 start and going 1-4 in his own starts before Garoppolo took over in December. Beathard completed 54.9 percent of his passes and had more interceptions (6) than touchdown passes (4), but he won over teammates with his ability to shake off big hits in the pocket (19 sacks).
"It's huge having already played last year in six games," Beathard said after Sunday's game. "That helps me going forward. Second time around, I think it will be a little easier."
Veteran nose tackle Earl Mitchell added: "He's a tough guy. He's been doing well. He's wise beyond his years, that's a tribute to Kyle and John Lynch in the type of guys they bring in to our locker room."
Backing up Beathard likely will be Nick Mullens, who's in his second season on the practice squad after going undrafted out of Southern Miss. Mullens completed 72.1 percent of his passes this past exhibition season; Beathard completed 60 percent.
Asked after Sunday's game if the 49ers will seek to add a veteran quarterback, either in free agency or via trade, Shanahan replied: "I don't think so. We'll think about that later but definitely happy with the guys we got. We'll have to do something. Add another to a practice squad or add a third. We definitely want three guys in the building."
Three weeks ago, the 49ers were reeling from the loss of another offensive stalwart to an ACL tear: running back Jerick McKinnon, who tore his in a non-contact drill at practice Sept. 1. The 49ers replaced McKinnon by turning to a committee of backs: Matt Breida, Alfred Morris and Kyle Juszczyk. Breida shares the NFL rushing lead with Ezekiel Elliott of the Dallas Cowboys (274 yards); Morris is more of a short-yardage specialist who scored his first 49ers touchdown Sunday; Juszczyk is a versatile option as a lead blocker, rusher and receiver.
Sunday's loss marked only the second in 10 career starts by Garoppolo. He was 20-of-30 for 251 yards with two touchdown passes for a 114.7 passer rating against the Chiefs. He got sacked four times, and he had three carries for 23 yards.
That last run resulted in one of the most devastating injuries in 49ers history.
"I think it was his fault," Chiefs linebacker Justin Houston told ESPN after the game. "I pray he's not hurt or nothing serious. As a quarterback you should step out of bounds. An inch wouldn't have made a difference. You've got to be smart, think about your team."
Left tackle Joe Staley had a different opinion: "Jimmy's just trying to be a ballplayer and trying to make a play. He wasn't running out of bounds. He was trying to get some extra yards for his team."
In other injury news, cornerback Richard Sherman is expected to miss a few weeks with a strained left calf and heel, NFL Network initially reported. Sherman had bone spurs removed in January from that leg, having also had to rehabilitate a ruptured Achilles in his right leg this offseason. He came out after four series against the Chiefs and left the locker room in an orthopedic boot.
