Douglas-Roberts has played in 12 games this season, averaging 1.6 points and one rebound in 8.6 minutes per game. The 28-year-old is a former second-round draft pick by the Nets in 2008.
By waiving Douglas-Roberts, the Celtics roster is now down to 14 players.
Boston (13-25) plays the Clippers in Los Angeles on Monday.
- Molly Geary