Bret MichaelsPoison frontman and celebreality star Bret Michaels has suffered a medical setback. The glam singer returned to the hospital after suffering from a 'warning stroke.' In medical terms, Michaels' condition is known as a transient ischemic attack.

Michaels noticed numbness on the left side of his body, including his face and hands. This prompted the return to a hospital and more tests. While doctors were diagnosing the warning stroke, it was also discovered that the singer has a hole in his heart, or patent forum ovale. The PFO is operable.

Doctor's stress they do not believe the warning stroke is connected to Michaels' recent brain hemorrhage. He is being treated with outpatient care and is now receiving a daily injection of Lovenox, a blood thinner to reduce the chance of blood clots.

This most recent health scare puts Michaels' appearance on Sunday's finale of NBC's 'Celebrity Apprentice' in jeopardy. Michaels is set to compete against Holly Robinson Peete to determine the winner of the current season. Michaels also has several shows booked during the summer, starting May 28 in Biloxi, Miss.

"I realize Bret wants to make a full recovery so that he can be active with his family, attempt to attend the finale of 'Celebrity Apprentice' and especially get back on the road to continue making music," Michaels' neurosurgeon Dr. Zabramski said in an online statement. "Without a doubt he is very determined to get healthy and make a 100 percent recovery. Medically speaking it is a fantastic attitude both mentally and physically for him to have. However, Bret's brain and body are not quite 100 percent yet, especially with the hole found in his heart."

Doctors promise more information about Michaels' condition next week.