Morris is averaging 11.5 points and 5.1 rebounds for the Wizards, who earlier Wednesday traded forward Otto Porter Jr. to Chicago.
Since the start of the season, Washington has saved $18.3 million toward the luxury tax. With the trade of Porter and now Morris, Washington is $232,000 below the threshold.
The Wizards’ moves come one day after the team announced that star point guard John Wall, already out for the season with a left heel injury, will miss most — if not all — of next season because he needs surgery on his left Achilles tendon.
Johnson is averaging 3.7 points and 2.1 rebounds off the bench.
ESPN’s Bobby Marks contributed to this report.