<P> Black players in professional American football Homosexuality in American football Concussions in American football Rugby union comparison Rugby league comparison Canadian football comparison Pro Football Hall of Fame College Football Hall of Fame Years in American football </P> <Dl> <Dd> NFL season - by - season </Dd> <Dd> College football season - by - season </Dd> <Dd> Glossary of American football </Dd> </Dl> <Dd> NFL season - by - season </Dd> <Dd> College football season - by - season </Dd>

How many times can you be nominated for the nfl hall of fame