The Boston Celtics will be without guard Marcus Smart for two weeks due to a lower leg injury.

Smart suffered the injury during the Celtics’ 120-95 win over the Brooklyn Nets. He limped off the court after banging knees with Brooklyn’s Thomas Robinson early in the fourth quarter. Celtics head coach Brad Stevens said Smart suffered a “subluxation of the proximal tib-fib joint,” reports ESPN.

The injury was initially diagnosed as a bone bruise, but Smart was rushed out of the locker room to have an MRI taken, reported the Boston Herald.

“They say a couple weeks-plus,” Stevens said about Smart’s timetable for return. “And there's no real end beyond a couple of weeks. It could be a couple weeks, it could be longer than that. Hopefully it gets a lot better sooner because obviously he's a big loss for us.”

Smart will not require surgery, but Stevens said he will be reevaluated by the team as he starts the rehab process.

“He'll listen to our doctors and they'll work together,” Stevens said. “They've gone and taken a bunch of images of it and they wanted to make sure. They've actually asked for second opinions on it, because it's a really unique injury. But it's not a long-term thing.”

In his sophomore season with the Celtics, Smart has been a valuable player so far, chipping in 9.8 points, 3.8 rebounds, 3.2 assists and 1.8 steals in 27.2 minutes per game. Smart’s tenacious defense is a major reason the Celtics currently have the best defensive rating in the league.

With Smart set for a spell on the sidelines, though, the Celtics will have to look for other players to step up and contribute.

“I think Jonas [Jerebko] will play some of those minutes; I think one of our young guys will play some of those minutes, to be determined on the night; and we'll go from there,” Stevens told ESPN. “That's why we have guys that are capable of stepping in and helping."