Former Notre Dame quarterback Blair Kiel, who also served as backup at the Green Bay Packers, died Sunday aged 50.
Kiel was rushed to a Columbus, Ind., hospital from a relative's house, Bartholomew County coroner Allen Smith told the Chicago Tribune.
Smith said doctors performed "advanced life support protocols" by were unable to revive him.
He was pronounced dead at 12:21pm local time, with an autopsy determining Kiel died of natural causes.
A Columbus native, Kiel played for Notre Dame from 1980-83, throwing for 3,650 yards and 17 touchdowns.
He went on to play for the Buccaneers, Colts and Packers over parts of seven NFL seasons, throwing 193 career passes.
Kiel had a number of legal run-ins in recent years. He was arrested in connection with a domestic battery and public intoxication incident in 2009. In 2010, he was arrested for drunk driving.
His nephew Gunner Kiel is now a highly touted freshman quarterback with Notre Dame.