Fisher is a stout defender who has averaged 8.6 points over his career. He will rank fifth among all active players in games played when he takes the court for Dallas.
Fisher is the current president of the NBA Players Association and was a prominent figure in last season's lockout that limited the season to 66 games.
Dallas will have to release one of its current 15 players to make room for Fisher. The Mavericks (7-9) have played the entire season without star forward Dirk Nowitzki as the former NBA MVP recovers from right knee surgery.