He was readmitted this week "after suffering numbness on the left side of his body, predominately his face and hands," the statement reads. After performing some tests, his doctors discovered a hole in the Poison star's heart.
Michaels, who taped his interview with Oprah Winfrey before this setback, is still expected to recover, but his participation in this Sunday's finale of Celebrity Apprentice is in doubt, as is his planned return to the concert circuit on May 28.
"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," says his neurosurgeon, Dr. Joseph Zabramski.
"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. Further tests will be conducted throughout the week."
Zabramski say the stroke and heart condition do not appear to be related to Michaels' brain hemorrhage. He has been given a regimen of blood-thinners and is being treated on an outpatient basis.
The 47-year-old singer, who is also diabetic, has been recovering at an Arizona ranch, with his family by his side.
"Even though these last few months have been tough on him and his family, especially this most recent setback, he is in good spirits, great medical hands and is positive and hopeful that everything is going to be OK," says publicist Janna Elias.
"He is up, walking, talking, continuing his daily rehab and very happy to be alive, but he has made it clear he is sick and tired of being in the hospital and is ready to rock again."
(Originally published May 20, 2010, at 2:56 p.m. PT)