Sep 24, 2018 4 min read

Jimmy Garoppolo’s addition last season immediately turned around the fortunes of the San Francisco 49ers. Now the 49ers will have to go back to life before Garoppolo for the rest of the season.

The Niners announced Monday that Garoppolo tore the ACL in his left knee while making a cut late in a loss at Kansas City, sidelining him for the rest of the season.

The injury deals a serious blow to the 49ers (1-2), who had planned their rebuild around Garoppolo and now must turn again to C.J. Beathard at quarterback.

The Niners struggled with Beathard and Brian Hoyer last season before the midseason addition of Garoppolo changed their fortunes. San Francisco won the final five games last year after Garoppolo took over as starter and the team rewarded him with a $137.5 million, five-year contract.

The 49ers will have to wait another year to earn dividends on that investment. Garoppolo got hurt in the fourth quarter of a 38-27 loss Sunday when he was scrambling toward the sideline and decided to cut up field instead of going out of bounds.

Garoppolo’s left knee buckled just before Kansas City cornerback Steven Nelson delivered a big hit, ending what was supposed to be his first full season as a starter after just three games.

Expectations were high in San Francisco this season that the team could end a four-year playoff drought after Garoppolo had a full offseason to immerse himself in coach Kyle Shanahan’s offense. But with Garoppolo and new running back Jerick McKinnon both knocked out for the season with torn ACLs in September, those high hopes have been put on hold.

Garoppolo had completed 59.6 percent of his passes with five TDs, three interceptions and an average of 8.1 yards per attempt for a 90 passer rating. While he hasn’t been quite as efficient as he was late last year after being acquired at the trade deadline from New England for a second-round pick, the Niners offense has been far more potent than it was before he took over as quarterback.

Beathard started five games as a rookie last year, completing 54.9 percent of his passes with four touchdowns, six interceptions, 19 sacks, 6.4 yards per attempt and a 69.2 passer rating that was second lowest in the NFL.

Miami DT questions ejection: Miami Dolphins defensive tackle Akeem Spence says he was trying to protect himself in a fight that led to his ejection for ripping off an opponent’s helmet.

Spencer was penalized for unnecessary roughness and ejected in the second quarter of Sunday’s win over Oakland following his skirmish with guard Kelechi Osemele.

The incident was doubly costly for Miami. The penalty negated a third-down sack and led to an Oakland field goal. And the Dolphins became short-handed in the front four when ends William Hayes and Andre Branch were sidelined with knee injuries.

Spence says the episode was typical of the Raiders.

Rosen to start for Arizona: Rookie Josh Rosen will take over as the Arizona Cardinals’ starting quarterback this Sunday against the Seattle Seahawks.

Rosen, the 10th overall pick in this year’s draft, replaced veteran Sam Bradford in Sunday’s 16-14 loss to the Chicago Bears with 4:31 left to play after three Arizona second-half possessions ended in turnovers.

Rosen couldn’t rally the Cardinals to a win, as he threw an interception to end his first drive and was sacked to end the second. But the rookie from UCLA completed four of seven passes for 36 yards and apparently showed coach Steve Wilks enough for him to make a change for the winless Cardinals (0-3).

“Josh plays with a lot of confidence. He gives us the opportunity to be successful,” Wilks said Monday.