According to the reports from Houston Chronicle, Yahoo Sports and ESPN on Friday, 30-year-old Rockets' center Yao Ming, who has a stress fracture in his left ankle early this year, has decided to retire and has informed the Rockets and NBA about his retirement.

Yao's contract had expired after this past season with the Rockets, who have missed the playoffs the last two seasons.

The 2.26-meter top overall pick by Houston in the 2002 draft, had been plagued by numerous injuries, the most recent of them a stress fracture in his left ankle suffered in a November 10 loss last season at Washington Wizards.

Yao, an eight-time All-Star, missed all of the 2009-2010 season after surgery to repair his broken left foot.

Last season the Rockets limited Yao's minutes to 24 per game, and made sure he didn't play in back-to-back games. Even so, Yao was hurt in his fifth game of the season. First diagnosed as a mild ankle sprain, the injury was later said to be an ankle bone bruise.

In his 486 NBA games, Yao averaged 19.0 points, 9.3 rebounds, 1.9 blocked shots and 1.6 assists.

However, official from Rockets has denied the report.

"We have not got any news about Yao's retirement," said Talung Lin, China's market manager of the Rockets. "We were surprised by the news spreading around here today."