Unable to work out an extension with James Harden, the Oklahoma City Thunder traded the Sixth Man of the Year to the Houston Rockets on Saturday night, breaking up the young core of the Western Conference champions.

The Thunder acquired guards Kevin Martin and Jeremy Lamb, two first-round picks and a second-round pick in the surprising deal that was completed Saturday night. Oklahoma City also sent center Cole Aldrich and forwards Daequan Cook and Lazar Hayward to Houston.

"I would love to Thank Oklahoma City for 3 amazing years!" Harden tweeted Sunday. "Teammates and Fans were thee best. The love will always be there. Thanks Again."

Wednesday's deadline to extend Harden or allow him to become a restricted free agent next July had been hanging over the Thunder from the moment they reported to training camp, but sources told ESPN.com's Marc Stein late Saturday the Rockets intend to sign the swingman to the max contract extension he was seeking before Wednesday's midnight deadline.

The Thunder offered Harden $55.5 million over four years -- $4.5 million less than the max deal Harden coveted and will get from the Rockets, sources told ESPN The Magazine's Chris Broussard.

"We wanted to sign James to an extension, but at the end of the day, these situations have to work for all those involved. Our ownership group again showed their commitment to the organization with several significant offers," Thunder general manager Sam Presti said in a statement.

"We were unable to reach a mutual agreement, and therefore executed a trade that capitalized on the opportunity to bring in a player of Kevin's caliber, a young talent like Jeremy and draft picks, which will be important to our organizational goal of a sustainable team."

The small-market Thunder had already signed Kevin Durant, Russell Westbrook and Serge Ibaka to long-term deals, and apparently realized Harden was going to want a bigger salary than they would offer.

Harden averaged 16.8 points and 3.7 assists last season, and joined Durant and Westbrook on the U.S. men's Olympic team. He struggled badly in Oklahoma City's loss to Miami in the NBA Finals, but the Thunder felt good about their chances of getting back there with another year of experience for their young stars, all 24 or younger.

The Thunder got back a good scorer in Martin, who has averaged 18.4 points in his eight NBA seasons, and a promising young player in Lamb, the No. 12 pick in the draft who helped Connecticut win the 2011 NCAA championship. He led Houston's summer league team in scoring with 20 points per game.

The Rockets rebuilt their roster in the offseason and hoped to land Dwight Howard. Houston traded or released just about every veteran except Martin, who was in the final year of his contract and due about $13 million this season.