Updated

The Houston Rockets and Boston Celtics tipped off Orlando Summer League play concerned about how major additions will fit into their success next year.

Prized free-agent Dwight Howard is heading to Houston and the Celtics have hired former Butler coach Brad Stevens to replace Doc Rivers.

Rockets coach Kevin McHale said Sunday morning Howard should be a "seamless fit." McHale says Howard can run the floor, block shots, finish "and that's all the stuff we want in our system."

Meanwhile, the 36-year-old Stevens says while watching summer league games, he's hiring a staff and watching a lot of film.

Celtics President Danny Ainge says they know Stevens is going to make some mistakes, but expect him to "get better and better, learn the NBA game and be able to lead."