Cal Stoll, a former University of Minnesota football coach,...

MINNEAPOLIS -- Cal Stoll, a former University of Minnesota football coach, underwent a heart transplant Thursday, a hospital spokeswoman said.

'He is in critical but stable condition in the intestive care unit,' said Mary Stanik, spokeswoman for the university hospital.

'That is normal for this type of surgery.'

She said Stoll, 63, went into surgery at 12:55 a.m. and came out at about 9:50 a.m.

Stanik said Stoll had been sick for months. 'I think he discovered he needed a heart transplant sometime last year,' she said.

Stoll had idiopathic cardiomyopathy, which is a degeneration of the heart muscle, of unknown origin, Stanik said.

Stoll coached the Gophers from 1972-78, posting a 39-39 record before quitting. He was replaced by Joe Salem.