Still, Tuesday's statement on Michaels' website said he was remaining positive and responding well to tests and treatments, and that he remained hospitalized and conscious in critical but stable condition.
"Even though today was a minor setback, doctors remain hopeful for a full recovery and plan to release more specific information next Monday," it read.
Doctors have yet to detail exactly what caused the bleeding in the first place. However, some neurologists have said they are optimistic that Michaels would survive the ordeal -- although the recovery process could take several weeks to months. In a bit of hopeful news, Michaels' father reported that his son could talk Friday, albeit with slurred speech.
He was also reportedly experiencing blurred vision.
"The fact that he's made it to a hospital and is apparently in some sort of reasonable condition ... that's a good sign," said Dr. Arno Fried, chairman of neurosurgery at Hackensack University Medical Center in Hackensack, N.J. "I would describe [Michaels' condition] as guarded. If the bleed has not caused too much damage, the possibility of recovery is quite good."
Dr. Daniel Barrow, who is chairman neurosurgery at Emory University Hospital, agreed that the latest reports suggest that Michaels' condition could be far worse.
"If he is hospitalized and speaking, he is in a much, much better category with regard to the possibility of a good recovery," Barrow said. "The best outcome is that he will be able to resume all of his previous activities with no complications. That is conceivable."
But, Barrow said, "There are many hurdles to cross before [Michaels] is out of the woods."
Part of determining exactly what these hurdles are depends on doctors' ability to determine the nature of the bleeding. Neurologists have said an aneurysm -- a balloonlike bulge in an artery that has the potential to rupture -- is a possible cause.
"Generally speaking, subarachnoid hemorrhage that is not the result of a ruptured brain aneurysm carries a much more favorable prognosis," Deshmukh said. "In Mr. Michaels' case, the fact that he is awake and talking is a very good sign.
"The report that Mr. Michaels is awake enough to respond to questions means that he is not at the end of the scale that has the worst outcome," said Dr. Alan Hoffer, director of neurotrauma at the University Hospitals Case Medical Center in Cleveland, Ohio. But, he added, "The presence of cranial nerve deficits, implied by his difficulty with vision and speech, means that he is likely in the middle of the scale."
The prognosis could be much worse if an aneurysm is, indeed, to blame. Dr. Nicholas Bambakidis, director of cerebrovascular and skull base surgery at University Hospitals Case Medical Center, said that many aneurysm patients suffer irreversible brain damage as a result of the hemorrhage itself.
"In cases in which there is no neurological damage initially, then patients must face the risk of the treatment, which consists of surgery to repair the aneurysm by closing it off such that blood no longer enters it," Bambakidis said. "If all goes well, patients then face a risk of stroke due to spasm in their normal blood vessels, which is caused by some type of reaction to the initial hemorrhage we do not fully understand , which and can occur up to three weeks after the bleeding.