However, sources told ESPN's Josina Anderson that X-rays on his knee were negative. Carter's agent, Carl Poston, later told Anderson that the early diagnosis "looks like Andre has a quad-related injury that will require surgery."
Carter was defending the run when he fell to the ground, clutching the left knee. He got attention from trainers on the field before being loaded onto a cart and wheeled off the field.
Carter seemed to have a sense of humor about the injury, tweeting early Monday that "On the brighter side. I think I can do the stanky leg dance."
He took a more serious tone in another tweet:
"God is great. Thank you for showing me and my family support this season. It's been a blast. Wouldn't change it for anything."
If Carter is lost for the season, which is a good possibility if he needs surgery, the Patriots would be losing their top pass rusher. He had 10 sacks through the first 13 games of the season.
"Losing Carter was a big loss there in the second quarter, but we had guys step up and they contributed throughout the game," Patriots coach Bill Belichick said.
In the locker room after the game, players talked about what Carter means to the Patriots.
"That's tough. Andre puts so much in with his leadership alone. He gives a lot to this team," defensive captain Vince Wilfork said. "To see him go down is tough. Any time someone goes down it's tough, but to see a guy like that go down -- he hasn't really won a lot in his career, but now he's winning, he's happy here, he's having fun, he's playing well -- it's a blow. We had to have guys step up. We stepped up and got this 'W' for him."
Patriots defensive end Mark Anderson said that while the team prepares for playing without injured players, losing Carter is a big blow.
"It's something we work on during practice. We all get reps," Anderson said. "Losing Andre, it's a big part of our defense. Hopefully it's nothing serious, but we were able to look past that and everybody stepped up and made plays.
"Andre is usually a very vocal leader on our team, everybody looks up to him, he's been there before and he's a great player. So losing him was very critical. Everybody just stepped up."
Chris Forsberg is a columnist and reporter for ESPNBoston.com. Mike Reiss of ESPNBoston.com contributed information.