The Heat said there is no timetable for Bosh'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 preseason physical. The Miami Heat regret that it remains unable to clear Chris to return to basketball activities, and there is no timetable for his return.
"We are not able to comment further in light of Article XXII, Section 3(e) of the NBA Collective Bargaining Agreement, which precludes a team from releasing certain medical information without a player's consent."
The 11-time All-Star forward is hoping to resume playing even though each of his last two seasons was cut short by blood clots.
Bosh has been examined by doctors in recent days in an attempt to be cleared for camp, which begins next Tuesday.
Last week, Bosh repeated what he said during the 2016 playoffs when he declared himself ready to play in the upcoming NBA season.
Bosh, eight months removed from his second blood clot-related health scare in a calendar year, posted a video of a private workout last month and went a step further in a podcast interview with Uninterrupted.
"I'm ready to play," Bosh said. "We've been talking about it for a long time. We released a statement back in May saying as soon as I'm ready to play as soon as possible, we'll play. And I'm ready. I've done all my work. I've done what I need to do working with the doctors."
If the medical issue keeps the 32-year-old Bosh out of action for good, he would be paid the remainder of his contract -- three years, $76 million -- but that wouldn't count against the Heat's salary cap after Feb. 9. Bosh averaged 19.1 points and 7.4 rebounds in 53 games last season when the second bout with clots began in February.