The 32-year-old Murphy, who signed with the Mavs in early November, averaged 4.6 points and 3.5 rebounds in 14 games during his Dallas tenure. He shot 36.1 percent from the floor and 31.4 percent from 3-point range.
Murphy, who started last week’s win over the New York Knicks, had bumped Brandan Wright from coach Rick Carlisle’s rotation. Wright has not played in four of the Mavs’ last eight games, including their two losses on the recently completed road trip.
Fisher, 38, is expected to sign with the Mavs on Thursday.
UPDATE: The Mavs made the moves official at 2:36 p.m., announcing the signing of Fisher and waiving of Murphy.