HOUSTON - Rockets star Dwight Howard is out indefinitely after receiving an injection in his right knee.

The team said Wednesday that Howard had a bone marrow aspirate injection and would begin rehabilitation immediately. The team said he will be re-evaluated in approximately four weeks, but did not offer a time for him to return to playing.

Howard last played on Jan. 23, when he left a game at Phoenix against the Suns with a sprained right ankle. He later reported swelling in his right knee.

At the time he was injured, Howard was second on the Rockets in scoring with 16.7 points per game and led the team with 11.2 rebounds a game. The Rockets have gone 3-3 since then heading into Wednesday night's game against Chicago.