Howard missed Sunday's game after spraining his ankle on Friday night. He started practice on Tuesday, but left after turning his ankle in the workout.
He says he hopes to play but isn't sure if he'll be ready to go.
Also on Tuesday, forward Terrence Jones went through a full practice for the first time since he was injured, and coach Kevin McHale says he could play on Wednesday.
Jones hasn't played since Nov. 3 because of nerve inflammation in his left leg. McHale is excited about the possibility of Jones returning and says he's been out so long his return will be like receiving a new player in a trade.