Chinese basketball star Yao Ming, who has a stress fracture in his left ankle, is upbeat to return to the court while his team remains cautious.

The 2.26-meter center, whose NBA career has been plagued by a series of injuries, has been sidelined since November 10 with what the Houston Rockets had called a bone bruise in the same ankle.

In a press release, the Rockets said his current injury was related to a prior one, and was discovered during his current rehabilitation.

"There is no timetable for his return at this time," the Rockets' statement said. "The team will have no additional comment at this time."

Despite the disappointing news, Yao remained upbeat.

"Right now, I still hope I can come back and play," he told sports website ESPN.com.

Yao, a seven-time All-Star, missed all of last season after surgery to repair his broken left foot.

This 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.

At the time, team doctor Tom Clanton said in a statement that Yao's troublesome left foot was "completely healed and the structural integrity of the foot is intact."

Yao, 30, was the top overall draft pick in 2002 but the 2005-06 campaign saw the first of many injuries when he broke a bone in his left foot with four games remaining in the season.

In the 2006-07 season he broke his right leg and missed 32 games, and a stress fracture in his left foot in February of 2008 caused him to miss the postseason.

He had pins inserted to stabilize the foot and played that year for China at the Beijing Olympics.

In 2008-09, Yao played 77 regular-season NBA games and had no problems with his foot until the second round of the playoffs, and when that hairline crack didn't heal he had the surgery that kept him out all of last season.

With Yao on the sidelines last season, Houston finished 42-40 and missed the playoffs. So far this season they are 10-15 and trailing in the Southwest Division.