The Mavs announced that Marion will not play in the team's three games remaining this week. He will be re-evaluated next week.
"It's a little minor thing to deal with," said Marion, a 14-year veteran who has averaged 8.0 points, 9.0 rebounds, 3.3 assists and 1.3 blocks in four games this season. "I'll go on and treat it and take one day at a time. It could have been a lot worse. Luckily, it's not."
Marion's injury, which occurred when his knee buckled after colliding with teammate Elton Brand in the third quarter Monday, leaves the 3-1 Mavs without anyone who played a postseason minute during the franchise's 2011 title season.
Dirk Nowitzki and Marion are the only players remaining on the roster who contributed during the championship run. Nowitzki continues to rehab from preseason arthroscopic surgery on his right knee.
"Now we've got our two best players out," said coach Rick Carlisle, whose team faces the Toronto Raptors at home and the New York Knicks and Charlotte Bobcats on the road the rest of this week. "It's going to be challenging. We've got to step it up and do it collectively with high intensity and playing our game. It's not easy."