Heavyweight boxer Muhammad Ali, right, visits Cleveland Browns running back and actor Jim Brown on the film set of movie "The Dirty Dozen" at Morkyate, Bedfordshire, England, on Aug. 5, 1966. (AP Photo)

Muhammad Ali scores a big right against Lyle Alzado's chin during first round of exhibition boxing match between former heavy-weight champ and Denver Bronco defensive end on Saturday, July 14, 1979 in Denver, Colorado. (AP Photo/EA)

Chicago Bears all-pro running back Walter Payton keeps a firm grip on playful punch world heavyweight boxing champion Muhammad Ali waves at him in Chicago, April 8, 1979. Ali received the Humanitarian of the Year award from the Coalition for Community Action, an organization promoting equal employment opportunities in the construction industry. (AP Photo/Charles Kenneth Lucas)

Lyle Alzado, left, defensive end for the Denver Broncos, gets in a left as he and Muhammad Ali battle on the ropes during eight-round exhibition fight on Saturday, July 16, 1979 at Denver?s Mile High Stadium. (AP Photo/EA)

Muhammad Ali, right, world heavyweight boxing champion, has a friendly bout with an old buddy from the U.S., Jim Brown, of the the Cleveland Browns football team, at Hyde Park in London, May 12, 1966. Brown is in England to take part in a new war film. Ali's regular sparring partner, Jimmy Ellis is in the background. (AP Photo)