"I had the last examination on Monday in the United States. I was told I had recovered 80 per cent. Doctors suggested me not to take full-strength training until late July. I'll join the national team tomorrow and take some tactical training," Yao told a news conference one day after he returned to China.

At the conference, which was attended by over 300 journalists from domestic and foreign press, Yao set off a "Yao Foundation" to help re-construct schools damaged by a severe earthquake in the Sichuan Province last month.

Yao said he was not sure whether to play Olympic warm-ups in July when China faces Australia and other contenders of the Stankovic Continental Champions Cup.

China is grouped with the United States and world champion Spain along with African champion Angola in Group B in the Olympic Games. The other two berths of the group will be decided in an Olympic qualifying tournament in July.

"This is not going to be an easy group. Firstly, we must make the second round. Our team, our country have made the preparation for a long time. We won't let our fans down," he said.

Yao said he feels good with his body. "I've done everything I can at this moment, but I cannot say whether I'm in good shape for competitions. I won't know it until I play with my teammates and see what will happen," he added.

"The Olympics is the biggest chance in my life. I'll try to enjoy the whole process. Important competitions are born with tremendous pressure, and that is how a great match identifies. There is big pressure for the Olympics and there is also big glory. They are not separated."

China will play its Olympic opener against the United States on August 10.