Updated

BEIJING (Reuters) - Yao Ming's participation at this year's Asian basketball championships remains shrouded in mystery as he battles back from his latest injury, Chinese media reported on Wednesday.

The towering NBA center, who suffered a serious ankle fracture playing for the Houston Rockets last November, has refused to speculate on his comeback.

But China's captain Liu Wei expressed cautious optimism about the appearance of the seven-foot six-inch (2.28-meter) Yao in Wuhan this September.

"Nothing is certain right now," Liu, a former team mate of Yao's at the Shanghai Sharks, told the China Daily.

The September 15-25 tournament guarantees the winners a spot at next year's London Olympics.

"Not only paving the way to London but winning back respect in Asia."

Yao, selected first overall by Houston in the 2002 draft, has caused Chinese interest in the NBA to soar, but has been cursed by injury throughout his career in the United States.

He played just over half a season in 2005-06 because of a toe infection and a broken foot, limiting his playing time over the following two years.

Yao then suffered a hairline fracture in his foot in 2008-09 before breaking his left ankle in Houston's loss to the Washington Wizards in November.

Despite the fact the 30-year-old only took off his protective boot a month ago, China placed their prized asset on their roster for summer training this month.

(Reporting by Alastair Himmer in Tokyo; Editing by Ian Ransom)