The move to IR could come as early as Tuesday.
Carter's agent told ESPN's Josina Anderson that Carter is expected to undergo surgery for a "quad-related injury" suffered in Sunday's victory over the Denver Broncos.
Carter was carted off the field after suffering what the Patriots first described as a knee injury late in the first quarter. A source told ESPN.com that X-rays on the knee were negative.
When asked by reporters Monday whether he expected Carter to return this season, coach Bill Belichick was evasive.
"We'll meet with our medical people this afternoon and see what they say based on the information they had last night," Belichick said. "We'll see how that goes."
Asked if there was any reason for optimism, based on the fact Carter was carted off, Belichick repeated his earlier thought.
"It just depends on what we're told. I'm not sure what their recommendation and what their information will be," he said. "We'll base our decision in large part on that."
Earlier, director of player personnel Nick Caserio said the team had not finalized any roster decisions related to Carter.
"We haven't done anything yet, as of today," Caserio said.
Carter seemed to have a sense of humor about the injury, tweeting early Monday: "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.
Practice squad defensive end/linebacker Markell Carter looks like a top candidate to be promoted if Andre Carter is placed on injured reserve. Markell Carter, the team's sixth-round draft choice from Central Arkansas, recently had his salary boosted from $149,000 to $306,000, a sign that the team views him as a player on the rise.
"Since he's been here, from training camp up to this point, I'd say he's certainly made progress," Caserio said. "The biggest thing with him is that he's coming from a lower level of competition, and that situation as well as not having an offseason program. He's worked hard. He's a player, whether it's during practice on the 'look' team, whether it's defensive snaps, post-practice, in meetings, he's worked hard and applied himself. He's made progress and I think that's what you want to see with any young player. We're happy to have him in the program."
Mike Reiss covers the Patriots for ESPNBoston.com.