Alex Karras - Telegraph Playing in the heart of the meat-grinder that is the line of scrimmage, defensive tackles are known more for brute force. Their job is to fight off two and three opponents at a time, clog up the middle, and, if possible, stop running backs "coming up the gut." Karras had the strength to do that, but atypically he had an unorthodox fleetness of foot and a wild, unpredictable way of attacking with his arms, possibly because he was so nearsighted that, in those pre-contact lens days, he failed to see what was in front of him and simply tried to hit everything that moved. His playing style earned him the nickname of Mad Duck. His unlikely physical agility was matched by a quickness of wit that also was atypical. Karras was suspended from the National Football League (NFL) for a year after violating the league's rules about betting on games. On his return, as captain of the Detroit Lions, he went to midfield for the coin toss that determines which side kicks off. Asked to call "head or tails" by the referee, he replied: "Sorry, sir, but I'm not allowed to gamble." Karras's quick-fire repartee attracted the author George Plimpton, who spent a few weeks with the Lions trying to play quarterback as part of the research for his bestselling book, Paper Lion. In the film of the book, Alan Alda played Plimpton but Karras played himself. His performance led to a booking on The Tonight Show With Johnny Carson, and then another and another. Soon Karras was America's favourite big man. Following Blazing Saddles, he built a career in television and film, playing against the big brute stereotype as the loving Dad in the sitcom Webster, and a homosexual bodyguard in Blake Edwards" Victor/Victoria. His final years were marred by dementia. American football is a brutal game. Its very real, unscripted violence is one of the main reasons why football is by far the country's favourite sport. Encased in helmets and pads, players are encouraged from an early age to be reckless with their bodies and hit opponents with every part of them, even their heads. In February 2011 one former player, Dave Duerson, committed suicide by shooting himself in the heart so his brain could be sent to Boston University, where a long-term study of brain damage to former players is being conducted. Earlier this year Karras joined a group of some 3,500 former NFL players suing the league and its official helmet-maker, Riddell. Their complaint alleges that the NFL has known for decades about the link between concussions and dementia. Karras, who suffered from cancer in addition to Alzheimer's, died of kidney failure. He is survived by his second wife, the actress Susan Clark, their daughter, and five children from his first marriage. Alex Karras, born July 15 1935, died October 10 2012