ALLEN PARK, Mich. — Detroit Lions safety Morice Norris, who returned to the team facility on Sunday after a scary injury in Atlanta on Friday night, is entering concussion protocol and will miss at least the next 10 to 14 days, according to head coach Dan Campbell.

Campbell said "everybody was fired up to see him" since Norris returned from Atlanta over the weekend. Norris, 24, was taken off the field at Mercedes-Benz Stadium in an ambulance after his head collided with Falcons running back Nathan Carter's knee during a preseason game. He was kept overnight at Grady Memorial Hospital in Atlanta for observation.

"That's a breath of fresh air, man," Campbell said of Norris' return to Allen Park. "That's hard when something like that happens, and you don't know. … I can't tell you the number of times I've seen guys with concussions, knocked out. I've had them myself. But when you have these, and then you don't know (anything) — you know they're breathing, but you don't know anything else. They're gone; it's just different."

The two teams returned to the field of play after Norris' injury, but it was clear neither team wanted to do so. The Falcons snapped the ball but did not run a play, allowing upward of eight minutes to run off the clock before an official stepped in and officially called the game.

Campbell clarified the process of resuming the game on Monday.

"(Falcons coach) Raheem (Morris) and I agreed that (kneeling the clock out the rest of the way) was what we were going to do," Campbell said. "We talked to (NFL official) Shawn Hochuli, (he) let us know, 'Hey, the game is still on.' We communicated with each other, we told Shawn we'd be taking knees. He said, 'I understand.' And that's the way it went, and then the game was canceled."