The arthroscopic surgery was performed by Dr. T.O. Souryal at the Texas Sports Medicine Clinic.
The 6-1 Van Exel has come off the bench in all six games this season and averaged 9.5 points and 3.3 assists per contest. He has shot 38 percent from the field, 40 percent from three-point range, and 92 percent from the free throw line.
Van Exel, acquired last February along with center Raef LaFrentz in a multi-player deal with Denver, has been forced to play a backup role to point guard Steve Nash in Dallas.
Ironically, LaFrentz also is sidelined for at least the next three weeks with a severely- sprained ankle.
Van Exel, who turns 31 later this month, averaged 21.4 points and 8.1 assists in 45 games with Denver last season before the trade. He has a penchant for shooting too much and feuding with coaches, but has accepted his role with the Mavericks.
With Van Exel out, the unbeaten Mavericks will use veteran Avery Johnson, who also was obtained in the Denver deal.
Dallas, which is the NBA's only remaining unbeaten team at 6-0, placed Van Exel on the injured list and activated 6-5 rookie guard Adam Harrington.
He is an undrafted free agent out of Auburn who began the season on the injured list with tendinitis in his left knee, and is an excellent long-range shooter.