Fred Hill, who coached Mills at Montclair State, said that many pro scouts loved his tape, but when they heard he was only 5'9", they lost interest. Conventional wisdom at the time held that middle linebackers had to be at least six feet tall to see over opposing offensive linemen and scan the field. In the same way it was after high school, Mills' lack of height held him back. After college, his Pop Warner Football coach Thomas Bevacqui Jr. was able to get Mills invited to the Cleveland Browns training camp after meeting with Browns coach Sam Rutigliano. Bevacqui told Rutigliano that Mills was the best linebacker that he had ever seen play the game. While Rutigliano admired Mills, he didn't think he had the size to play in the NFL and cut him from the team. Mills then tried out with the Canadian Football League's Toronto Argonauts but did not make the team.