San Francisco 49ers head coach Kyle Shanahan said the team fears quarterback Jimmy Garoppolo tore the anterior cruciate ligament in his left knee on Sunday.

Sep 23, 2018; Kansas City, MO, USA; San Francisco 49ers quarterback Jimmy Garoppolo (10) is taken off the field after an injury in the second half against the Kansas City Chiefs at Arrowhead Stadium. Jay Biggerstaff-USA TODAY Sports

Garoppolo was carted off the field after the knee buckled before he took a big hit along the sidelines from Kansas City Chiefs cornerback Steven Nelson.

Garoppolo could have stepped out of bounds but instead chose to fight for extra yardage on third-and 20 with his team trailing by 14 with a little over five minutes left in the fourth quarter. He planted his left leg and lowered his right shoulder into Nelson, who drilled the quarterback. The 49ers’ medical staff evaluated Garoppolo’s left leg before he limped toward the sideline. Garoppolo later was carted to the locker room.

Cornerback Richard Sherman (calf) and running back Matt Breida (knee) also left early, although Breida returned despite what initially looked like an ugly injury. Sherman limped off late in the second half and did not return. He was seen after the game with his left leg in a boot and is expected to have an MRI on Monday.

--Tennessee Titans quarterback Marcus Mariota took over after replacement starter Blaine Gabbert went down with a concussion in the first quarter against the Jacksonville Jaguars.

Gabbert was examined on the sideline after taking a hard hit from defensive tackle Malik Jackson, then was taken to the locker room to be evaluated and was diagnosed with a concussion. Jackson was called for lowering the head to initiate contact, and the Jaguars were hit with a 15-yard penalty on the play.

Gabbert had completed one pass on three attempts for 8 yards when he left the game. Mariota was out of the starting lineup with a pinched nerve in his right elbow. Cornerback Adoree’ Jackson also left with a concussion and did not return.

--Los Angeles Rams cornerback Marcus Peters was carted to the locker room after sustaining a right lower leg injury in the second quarter against the Los Angeles Chargers.

According to an ESPN report, Peters has a calf injury and will not return. The team called it an ankle injury and deemed him questionable to return.

Peters remained down after a catch by Antonio Gates and did not put weight on his right leg while being helped off by trainers. CBS sideline reporter Evan Washburn said on the broadcast that trainers were looking at Peters’ calf and Achilles area on the sideline. Peters was helped to a cart and taken to the locker room. Outside linebacker Dominique Easley also was ruled questionable to return with a knee injury.

--Cincinnati Bengals wideout A.J. Green sustained a groin injury in the first half against the Carolina Panthers and did not return.

Green went down in the second quarter and limped off the field but was ruled probable to return. Half an hour later, the team updated his status to questionable, but he remained on the sideline without a helmet or gloves.

Green had five grabs for 58 yards before leaving.

--New York Giants tight end Evan Engram left in the second quarter against the Houston Texans with a knee injury and quickly was ruled out.

Engram limped off the field after making a 19-yard catch early in the second quarter and was taken to the medical tent for evaluation. The team then ruled Engram out, though he remained standing on the sideline in full equipment.

The 19-yard catch was Engram’s only grab of the day.

--Green Bay Packers defensive tackle Muhammad Wilkerson was carted off the field and taken to a nearby hospital after injuring his ankle against the Washington Redskins.

Wilkerson could not put any weight on his leg after he was inadvertently hit low by teammate safety Kentrell Brice on a defensive play. Fellow defensive linemen Kenny Clark and Mike Daniels comforted Wilkerson as a cart approached.

Right tackle Bryan Bulaga also left and did not return after sustaining a back injury. Jason Spriggs stepped in at right tackle. Meanwhile, Redskins right tackle Morgan Moses sustained a concussion and also was ruled out for the game.

--Atlanta Falcons safety Ricardo Allen left in the second half against the New Orleans Saints after sustaining a non-contact injury to his left calf.

Allen was unable to put any weight on his left leg as he was helped off. Head coach Dan Quinn declined to discuss the injury in detail afterward, saying he didn’t want to speculate about the severity.

The Falcons already lost strong safety Keanu Neal (ACL) for the year, prompting the move of Allen to strong safety, with Damontae Kazee taking over at free safety. Linebacker Deion Jones (foot) is out for at least eight weeks after going on injured reserve, and the Falcons’ defense was also without defensive ends Takk McKinley (groin) and Derrick Shelby (groin) on Sunday.

--Oakland Raiders right tackle Donald Penn sustained a concussion against the Miami Dolphins and did not return.

Penn went down in the first half and was ruled out in the third quarter. He was replaced by T.J. Clemmings.

In the same game, Dolphins defensive end William Hayes left with a knee injury and was ruled out.

--New Orleans Saints cornerback Patrick Robinson was carted off the field with a left leg injury in the second half against the Atlanta Falcons.

Robinson went down and appeared to be in significant pain while being treated on the field. He could not put weight on the leg before being taken off.

Nola.com reported that initial tests indicated Robinson has a high-ankle sprain.

--Chargers punter Drew Kaser was carted to the locker room with a right shin injury after getting hit on a blocked punt in the first half against the Rams.

As Rams linebacker Corey Littleton blocked Kaser’s punt in the end zone -- which the Rams recovered for a touchdown -- his helmet appeared to hit Kaser’s shin. The team officially called Kaser questionable, calling it only a leg injury.

Kaser had punted twice for 102 yards before leaving. Kicker Caleb Sturgis was expected to punt in his stead, while quarterback Philip Rivers was the holder on Sturgis’ extra point late in the second quarter.

--Field Level Media