(CNN) -- Chinese basketball star Yao Ming has suffered a fresh injury setback which could place his NBA career in jeopardy.
The seven-time All-Star has a stress fracture in his left ankle, his Houston Rockets team announced on its website.
Yao, 30, has been sidelined since November 10 after playing just five games in the current NBA campaign.
The giant 7ft 6 (2.29 meters) center also sat out all of last season after fracturing a bone in his left foot and undergoing major surgery.
The Rockets said his stress fracture is related to the previous injury and was discovered by an MRI scan after problems emerged during his rehabilitation program.
"There is no timetable for his return at this time," said the statement.
Yao averaged 10.2 points and 5.4 rebounds a game in his five games this season for the Rockets, whose playoff hopes have been dented by his absence.
Yao was the first pick in the 2002 NBA draft and has built up a reputation as one of its leading players during his career at Houston.
A national hero in China, Yao has represented his country in the 2004 and 2008 Olympics, helping them to the quarterfinals on each occasion.
He carried China's flag at the opening ceremony for the 2004 Games in Athens.