With 44 seconds left in the game, Foles dropped back to pass and attempted to avoid the Vikings' rush, but Minnesota defensive end Ifeadi Odenigbo caught hold of the veteran quarterback and drove Foles backward into the ground.
Bears coach Matt Nagy, in his postgame availability, said Foles suffered a hip or leg injury. A source told ESPN's Adam Schefter that the initial diagnosis was a hip pointer and that Foles was scheduled for more tests on Tuesday.
"You never want to see anybody go down, my team or the other team," Bears running back Cordarrelle Patterson said. "Being a part of that, it hurts, man. We know how much work Nick puts in each and every day, the grind he put in. To see a guy like that go down, it's heartbreaking. I just wish the best for him and his family. Just keep praying for him. I hope everything works out."
Foles stayed down on the field for over a minute until the cart came out and transported him to the locker room.
"He's a tough dude, and he was in a lot of pain," Nagy said. "When you see that and you're down there with him, you feel for him just because you don't know how bad it was. So that part is hard.
"Again, the protection and where we're at with getting the ball out -- quick game, getting the ball out and getting the ball out with max protection -- is something we've got once again to look at."
Foles finished the night 15-of-26 for 106 yards and one interception.
Veteran signal-caller Tyler Bray entered the game for Chicago's final drive. Former second overall pick Mitchell Trubisky, who lost the starting job to Foles in Week 3, was inactive because of a shoulder injury.
"I don't know about Mitch," Nagy said after the loss. "I think there's a possibility, but I don't know that for sure. We just have to take it day by day."
The Bears (5-5) are on a bye week and next play at the Green Bay Packers on Nov. 29.