CHICAGO (CBS) — White Sox reliever Danny Farquhar is stable but in critical condition after tests show he suffered a brain aneurysm before he was carried out of the dugout during Friday night’s game.

Doctors say brain aneurysm are more common than people think, however they can occur in older patients.

CBS 2 spoke with a professor of neurosurgery at Northwestern University hospital who explained how lucky Farquhar was.

“Ruptured brain aneurysms are very serious. They are life-changing events,” said Dr. Babk S. Jahromi of Northwestern’s Department of Neurological Surgery. “Only two-thirds of patients survive to get to the hospital. There are subsequent challenges that can occur in the first week or two after the aneurysm has ruptured.”