HOUSTON — James Harden plans to sign a long-term extension with the Houston Rockets before the regular season begins.

The reigning Sixth Man of the Year joined his new team Sunday after he was traded to the Rockets from Oklahoma City late Saturday. The Thunder acquired guards Kevin Martin and Jeremy Lamb, two first-round picks and a second-round pick in the surprising deal. Oklahoma City also sent center Cole Aldrich and forwards Daequan Cook and Lazar Hayward to Houston.

“It happened so fast, it happened very fast,” Harden said. “But this is the position I’m in in now. Just have to make the best out of it. I’m with Houston now. I just have to come in here and play hard and win games.”

Thunder general manager Sam Presti said Houston was able to offer Harden a contract that Oklahoma City could not.

“Quite honestly, the value of the trade was greater based on the fact that the Rockets could offer him the contract that he was seeking,” Presti said. “By doing it when we did it, it allowed the Rockets to secure — or I believe it will allow the Rockets to secure him and James will get the contract that he was seeking. And because of that, we were able to capitalize on the trade and probably get a little bit more than we would have if we would have waited.”