UPDATE: Bret’s doctor now thinks the stroke was related to Michaels’ earlier medical problems.

Less than 24 hours after Bret Michaels was seen smiling on Oprah, we’ve learned that the singer had to reenter the hospital this week,

According to a release posted on both the singer’s Facebook page and website, the 47-year-old experienced was readmitted after experiencing numbness on the left side of his body. Doctors have diagnosed the problem as a “warning stroke” that was related to a hole discovered in his heart.

The good news? The condition - which is not believed to be connected to Michaels’ recent brain hemorrhage - is considered operable and treatable. It is not yet known what this will mean for his upcoming engagements as further tests will need to be conducted. In the meantime, “Bret will be treated with outpatient care which includes a daily injection of Lovenox (a blood thinner to reduce the chance of blood clots) and blood tests.”

You can read the full statement about Bret’s status after the jump.

Bret Michaels was readmitted to the hospital this week after suffering numbness on the left side of his body, predominately his face and hands which doctors described as a Transient Ischemic Attack (TIA) or warning stroke. While MRI and CT scan tests were being conducted, Michaels also received a Doppler Ultrasound of his legs and lower abdomen looking for blood clots and most importantly an Ultrasound Bubble Test of his heart was conducted which proved positive for a Patent Forum Ovale (PFO), a hole in the heart. Dr. Zabramski (Bret’s neurosurgeon), Dr. Becker (who ordered the test), Dr. Cook (who conducted the test) and Dr. Frey (Director, Outpatient Stroke Program) all confirmed the results.

Dr. Zabramski states “There is no doubt that the positive Patent Foramen Ovale (PFO) is devastating news to Bret and his family. The good news is that it is operable and treatable and we think we may have diagnosed the problem that caused the Transient Ischemic Attach (TIA) or warning stroke; however we feel it is highly unlikely this is connected to the brain hemorrhage he suffered just a few weeks earlier. Once again it is great that he quickly reacted to the severe numbness and got to the hospital immediately.”

Dr. Zabramski continues, “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. Without a doubt he is very determined to get healthy and make a 100% 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% yet, especially with the hole found in his heart. Further tests will be conducted throughout the week and I will have more information next week as to how this Patent Foramen Ovale (PFO) will be treated. For now, Bret will be treated with outpatient care which includes a daily injection of Lovenox (a blood thinner to reduce the chance of blood clots) and blood tests.”

Bret’s rep, Janna Elias, states “Bret wants everyone to know he cannot thank you enough for all of the well wishes, prayers, and good vibes you have sent his way. 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. 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.”