<P> A winless season is a regular season in which a sports team fails to win any of their games . The antithesis of a perfect season, this ignominy has been suffered twelve times in professional American football, six times in arena football, three times in professional Canadian football, once each in American professional lacrosse and box lacrosse, more than twenty - five times in major Australian football leagues, thirteen times in top - level rugby league, at least twice in top - level rugby union, and twice in English county cricket . </P> <P> Because of the relatively small number of games played in college and professional football seasons, there is a possibility that a particularly inept team will not manage to win any games . Before overtime was used consistently, teams might tie a game without winning one; these are generally counted in lists of winless seasons . This is because, during eras before overtime was introduced to American football, leagues generally ignored tied games when calculating winning percentage . </P>

How many times has a nfl teams lost every game