The 7-foot-6 Yao, voted the starting center for the Western Conference for the All-Star game on Feb. 17, told team officials he felt sick when he arrived at the Toyota Center for a workout on Sunday morning, coach Rick Adelman said.

"The doctors looked at him and they don't think it's worth the chance," Adelman said. "We'll just have to move on."

Yao, leading the Rockets with 22.1 points and 10.7 rebounds per game, had started every game this season. Adelman planned to start either Carl Landry or Luis Scola, both NBA rookies, in Yao's place.

"The only thing that really changes for us is the fact that, without Yao, there's nobody with a low-post presence he has," Adelman said. "As far as our offense, Carl or Luis, they're interchangeable. Defensively is where there are some things we're going to have to be aware of."