BOSTON - Gerald Green had no shootaround, no practice to get ready to play for the Rockets against the Celtics on Thursday. But the Rockets signed him because they needed him to step in immediately and take some of the load off Trevor Ariza in particular.

Ariza had played at least 40 minutes in six-consecutive games since Luc Mbah a Moute went out with a dislocated shoulder. Mbah a Moute is expected to miss another week.

"He's a vet, he knows how to play," Rockets coach Mike D'Antoni said. "We're not real complicated. If he can take a few minutes off Trevor, that's what we'll use him for. We're just really shorthanded on the wings. Obviously, he's played at a good level before."

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Celtics coach Brad Stevens said Green's skills are a perfect fit with the Rockets after he had a significant role with Boston last season. Green, a 10-year veteran who had played for eight teams (including one game with the Rockets in the 2007-08 season), went to training camp with the Bucks last season and was released. He signed a one-year, non-guaranteed contract with the Rockets on Thursday.

"Obviously, he's a guy that can score the ball," Stevens said. "He's a guy that's been doing it for a long time. He was fun to have around. He's a big reason we advanced out of the first round. I thought him starting in that Bulls series and spreading the floor and being able to guard up a spot (matching up with power forwards) ... is no easy task.

"Gerald is a really accomplished guy. I think it makes a lot of sense. He fits perfect for how they play. I wish they would have waited for tomorrow, but I'm really happy for Gerald."