MIAMI • Miami Heat star Chris Bosh, who missed the second half of each of the past two National Basketball Association (NBA) seasons because of blood clots, failed a pre-season physical test and will not be able to return to action, his team said on Friday.

The Heat added that there is no timetable for the 32-year-old's return.

"The Miami Heat and Chris Bosh, in consultation with team doctors and other physicians, have been working together for many months with the mutual goal of having Chris return to the court as soon as possible," the team said in a statement.

"Chris has now taken his pre-season physical test. The Miami Heat regret that it remains unable to clear Chris to return to basketball activities, and there is no timetable for his return."

Bosh, who has not played since Feb 9 after the emergence of blood clots in his calf, said last week he was ready to play in the upcoming NBA season.

He also missed the second half of the 2014-15 season with blood clots, with one moving to his lung and forcing him into an extended hospital stay.

The forward posted a video of a private workout last month and went a step further in a podcast interview with Uninterrupted.

"We've been talking about it for a long time. And I'm ready. I've done all my work. I've done what I need to do, working with the doctors," Bosh said.

Heat president Pat Riley and coach Erik Spoelstra have been supportive of Bosh but point to the importance of medical input.

If the medical issue keeps Bosh out of action for good, he would be paid the remainder of his contract - three years, US$76 million (S$103 million) - but that would not count against the Heat's salary cap after Feb 9.

Bosh averaged 19.1 points and 7.4 rebounds in 53 games last season before the second bout of clots.

Miami's pre-season training camp begins next Tuesday.

"I've made it clear from the jump if I'm ready to play I want to play," Bosh added. "I will play basketball in the NBA. I'm confident."

AGENCE FRANCE-PRESSE, REUTERS