Mankins will not need surgery, according to the report, and is hoping to return for the playoffs.
The injury occurred on the second series of Saturday's win over the Dolphins, knocking Mankins from the game. On a run by Danny Woodhead, Dolphins defensive lineman Jared Odrick fell on Mankins' leg. Mankins stayed in the game for the next play before coming off the field on fourth down.
Mankins was examined by team trainers and doctors on the bench and a wrap applied by trainers to the knee. He tested it, but he was unable to return.
Patriots left tackle Matt Light, who was also missing Saturday as a game-day scratch with a right ankle injury, said Mankins was in meetings with him all day Tuesday and seemed optimistic about his eventual return, even as he described his reaction to seeing Mankins sidelined as "not good."
"He's a tough guy, a guy that's never missed a practice or a game, or had any of those kind of issues," Light said. "When you see that happen, it's always tough to watch. But I'm sure the cowboy will ride again. He'll be good."
As for his own injury situation, Light said he's "getting there." It appeared he was hurt during warmups before Saturday's 27-24 victory over the Dolphins. He was being watched closely by team doctor Thomas Gill as he loosened up on the field before the game and kept looking down at his right foot as he worked on getting out of his stance.
"I just wasn't able to go the other day, unfortunately," Light said. "It's a tough deal, game day, making that decision. But we'll work this week and get back out there. It's feeling better."
With two starters out, the makeshift offensive line struggled to protect Tom Brady in the first half but was much improved in the second half, when the Patriots rallied from a 17-0 deficit to beat Miami. Donald Thomas and rookies Marcus Cannon and Nate Solder were all thrust into critical roles.
Solder shifted from right tackle to left tackle in place of Light. Cannon replaced Solder at right tackle and Thomas replaced Mankins at left guard.
"It's crazy, but playing this game, even in college, stuff like that happens all the time," Thomas said. "There is a guy that can't play and all of a sudden you're thrust in to play at the drop of a dime. You've just have to be ready to go. I didn't think it would happen that quick, but it did. I had to rise to the challenge."
"I think those guys all fought hard," Light said. "To come back in the second half that way and battle back, and get a win, that was a heck of an effort. We have a lot of things we have to correct, and there always a lot of things we have to do better. But those guys did a great job out there. Of course, guys stepping up and playing positions they hadn't practiced, and going through plays they haven't run -- maybe at all in some cases -- it's not an easy task."
If both Mankins and Light miss Sunday's game against the Buffalo Bills, the Patriots could opt for a similar alignment on the line or, with much more time to prepare, could change things up again.
Information from ESPNBoston.com's Mike Reiss and Mike Rodak was used in this report.