HOUSTON -- The Houston Rockets have orally agreed on a three-year contract with Yao Ming that includes an option worth an estimated $18 million.

Yao, the 7-foot-5 center from China, was picked first overall by the Houston Rockets in the June draft.

The value of the first three years of the deal is $12,442,680, as slated by the NBA rookie salary guidelines. The deal also is expected to include an option for a fourth season which will bring its total value to about $18 million.

"We expect that he will be able to come to the United States shortly after the Asian Games have concluded on Oct. 14,'' Rockets general manager Carroll Dawson said in a statement Thursday.

Yao's contract is actually three separate agreements involving the Chinese Basketball Association, Yao and the Rockets, according to ESPN.com's Darren Rovell. Yao's agent and cousin, Erik Zhang, declined to specify how much of Yao's salary and endorsements will go to the Chinese National Sports Bureau and the basketball association.

Zhang did say that the contract will include a "love of the game" provision allowing Yao to play for the Chinese national team.

"The provision ensures Yao's commitment as a national team player to serve his country whenever called upon," Zhang said.

The CBA has said it would address the matter after Yao finishes playing for China in the Asian Games, which end Monday.

Rockets officials have said they don't expect a problem.

"We expect that he will be able to come to the United States shortly after the Asian Games have concluded on Oct. 14," Rockets general manager Carroll Dawson said in a statement.

On Tuesday, Yao scored nine points and blocked seven shots in China's 92-51 victory over the Philippines in the Asian Games in Busan, South Korea.

Yao has averaged 14.2 points as China has beaten five Asian opponents by an average of almost 50 points per game.

The Associated Press contributed to this report.