KANSAS CITY, Mo. _ Jimmy Garoppolo's fourth-quarter knee injury overshadowed all else that went wrong in the 49ers' 38-27 loss Sunday to a high-powered Kansas City Chiefs team.
Garoppolo got hurt on a third-down scramble to the Chiefs 7-yard line, where he endured a helmet-to-helmet collision with cornerback Steven Nelson with 5:17 remaining.
The team fears Garoppolo might've torn his ACL, which would end his season.
Garoppolo slowly walked back to the 49ers sideline, and after being evaluated in the medical tent, he was carted into the locker room as the Chiefs (3-0) wrapped up what figured to be a lopsided win.
Staking the Chiefs to five touchdowns in five series put the 49ers (1-2) in a 35-7 hole. Patrick Mahomes and his talented cast took advantage of the 49ers' slew of penalties, injuries and first-half ineptitude by the 49ers defense
The 49ers saw several other starters leave with injuries, although some returned: cornerback Richard Sherman, linebacker Reuben Foster, free safety Adrian Colbert, cornerback Jimmie Ward, right guard Mike Person and running back Matt Breida.
Breida, Foster and Person returned to action, doing so amid an improbable comeback bid that ultimately fell short against the NFL's top-scoring team.
Blown coverages, missed tackles and multiple penalties hurt the 49ers defense, allowing Mahomes and a talented supporting cast to take advantage with creative play calls and overall dominance. Mahomes, in his first home start, threw three touchdown passes in the second quarter gave him 13 to start the season, surpassing Peyton Manning's 2013 record for most through three games.
Trailing 35-7 at one point, Garoppolo did try rallying the 49ers offense, and his 11-yard touchdown pass to Marquise Goodwin pulled them within 35-16 after their first possession of the second half. Garoppolo finished 20-of-30 for 251 yards and two touchdowns.
C.J. Beathard replaced Garoppolo and promptly threw a touchdown pass to George Kittle, only to have it nullified by a Kyle Juszczyk pass-interference penalty.
Garoppolo, who the 49ers signed to a massive contract (five years, $135 million contract) in the offseason, has been hit too often amid their start. He got sacked four times this game, and six in last Sunday's home-opening win over the Lions.
The 49ers historically haven't fared well at Arrowhead, where they've now lost five in a row. After Joe Montana outdueled Steve Young 24-17 in 1994, the 49ers lost 44-9 in 1997, 41-0 in 2006 and 31-10 in 2010.
For the third time in four weeks, the 49ers (1-2) play on the road next Sunday, when they visit the Los Angeles Chargers.
