X-rays on the wrist were negative, and he's listed as day to day. The team won't practice Saturday and his status for Sunday night's home game against the Golden State Warriors is uncertain.
Marion finished with 13 points in 14 minutes off the bench, making six of eight field goals and grabbing five rebounds.
"No. 1, he's one of our best players and No. 2, he had a great game going," Mavericks coach Rick Carlisle said. "He was one of the main reasons we were able to get some momentum going into the halftime."
Late in the first half, the Mavericks went on a 11-2 run to end the half trailing by just five points. Jason Terry and Marion scored all the points during the run, but Marion ran into one of his teammates near the end of the half and injured the wrist.
"It was just bothering him too much to come back," Carlisle said. "So that was a big loss. But the guys battled in the second half like crazy, and we just couldn't get there."
The Mavs appeared to be recovering from a recent injury bug with with the return of center Brendan Haywood, who missed the previous two games with a stiff back. Haywood said he felt good before Thursday night's game at Golden State but was held out as a precaution. He scored two points in 18 minutes off the bench Friday.
Small forward Peja Stojakovic has missed the past six games with a stiff neck. His status hasn't been determined.
The loss of Marion forced the Mavericks to play with a smaller lineup, giving front-court players Brian Cardinal and Ian Mahinmi more minutes. Forward Tyson Chandler's foul trouble also hurt the team -- he picked up his fifth foul with 11:26 to play in the fourth.
Without Chandler and Marion for the bulk of the second half, the Mavericks struggled to score.
"It's tough," said Dirk Nowitzki, who led the Mavericks with 23 points. "[Marion] was just playing well there at the end of the second quarter [when] he had a run, made a couple of moves and had a bounce in his step."
Marion was not available for comment after the game.