Yao Ming is staying tight-lipped on his National Basketball Association future once his contract with the Houston Rockets expires at the end of this month.

The injury-hit center declined to answer questions about his plans at an appearance on behalf of the Special Olympics in Beijing yesterday, saying he didn't want to discuss anything not related to his work with the charity. He said previously he hoped to stay with Houston, now coached by Kevin McHale. The 2.3-meter All-Star has said doctors tell him his surgically repaired left ankle is healing properly, but that he won't know before later this summer if he'll be able to play next season. He becomes a restricted free agent on July 1.