New York Giants running back Saquon Barkley is out against Chicago after he hurt his right knee early in the second quarter.
The Giants said Barkley was getting X-rays and would undergo further evaluation on Monday.
Barkley went down hard on the Bears sideline after trying to fend off safety Eddie Jackson on a 6-yard carry. The 2018 NFL Offensive Rookie of the Year dragged his right leg behind him as he was helped back across the field to the Giants sideline.
After a short conversation with trainers, Barkley got on a cart and was driven into the tunnel.
Barkley also seemed to be shaken up after he was tackled at the end of an 18-yard run late in the first, but he quickly re-entered the game.
The 23-year-old Barkley struggled in New York's season-opening loss to Pittsburgh, finishing with just 6 yards on 15 carries. He also was criticized by former Giants running back Tiki Barber for his pass-blocking skills.
Some other teams lost key players in the first half of games on Sunday.
Denver Broncos backup quarterback Jeff Driskel replaced starter Drew Lock after he injured his right shoulder on a hit from Pittsburgh Steelers linebacker Bud Dupree. Lock was scrambling when he was tripped up by Steelers linebacker T.J. Watt. Dupree then hit Lock while the quarterback stumbled, forcing Lock to fumble and sending Lock's throwing shoulder into the Heinz Field turf.
One week after the Indianapolis Colts lost running back Marlon Mack with a season-ending ruptured Achilles tendon, second-year receiver Parris Campbell was carted off the field after appearing to injure his left knee.
Campbell was injured on the Colts second play. Vikings safety Harrison Smith made the hit and Campbell immediately reached for his knee. He missed most of his rookie season with injuries and went into the concussion protocol after an August traffic accident.