what did dick butkus die from

Dick Butkus, a Pro Football Hall of Famer and former Chicago Bears linebacker, died at the age of 80. According to a statement released by the team, Butkus family confirmed that he died in his sleep at his home in Malibu, California. The cause of his death has not been disclosed in the search results. However, it is known that Butkus tenacious style of playing football took a toll on his health, and a right knee injury forced him to retire at the age of 31 following the 1973 season.