Houston ? Houston Rockets center Yao Ming is retiring, according to a report by Yahoo! Sports.

The 7-foot-6 Chinese star, plagued by lower-body injuries in the second half of his career, has informed the league office that his playing career is over, the website reported.

The Rockets declined to comment on the report because of the lockout, and the NBA has not received official retirement paperwork from Yao.

Yao’s contract expired after last season, and the Rockets said they were interested in re-signing him if he came back healthy. Yao said in April in China that his professional future depended on his recovery from a stress fracture in his left ankle.

John Huizinga, one of Yao’s American agents, would not confirm the report during a phone interview Friday. He said Yao’s recovery was “on track,” but Yao’s future with the Rockets has been uncertain for some time.

“He’s really enjoyed his time in Houston,” Huizinga said. “If he feels that he’s recovered enough to play, and if the lockout ever ends, and if the Rockets are interested in him, then there’s certainly a good chance he’ll stay in Houston.

“But there are a whole lot of ‘ifs’ in that statement.”

An eight-time All-Star selection, Yao averaged 19 points and 9.2 rebounds in his eight seasons, but his impact on the league goes far beyond the numbers.

Yao single-handedly expanded the NBA’s reach throughout Asia, spiking merchandise sales and TV ratings for games after the Rockets made him the top overall pick in the 2002 draft.

Marc Ganis, president of Chicago-based consultancy SportsCorp, said Yao’s worldwide impact on the league will probably never be duplicated by another player.

“There’s never been anything like him before,” Ganis said, “and I doubt we’ll ever see anything like him again.”

Yao played for the Chinese national team in the six summers before he joined the NBA.