A winless season is a regular season in which a sports team fails to win any of its 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, over twenty times in top-level rugby league, at least twice in top-level rugby union, and twice in English county cricket.
Gridiron football
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 games in the regular season was instituted, teams might tie a game without winning a game; these are still 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.
Because NFL teams do not all play one another each season, it is possible for multiple teams to go winless (or also, for that matter, to go undefeated in the regular season). This was common in the NFL's early years as scheduling was not standardized and teams entered and left the league regularly. Since 1935, multiple simultaneous winless seasons has only happened once, in 1944 when both Brooklyn and Card-Pitt finished 0–10 in a season where rosters had been decimated (and parity disrupted) by wartime enlistments.
National Football League
8 or more games
The Rochester Jeffersons went a combined 0–21–2 from 1922 to 1925, but played only partial NFL schedules in those years (0–4–1, 0–4, 0–7 and 0–6–1, respectively). They also had another winless season in 1911 going 0–1–3 in the New York Pro Football League.
One honorable mention is the 1980 New Orleans Saints. The team lost their first 14 games and finished with a 1–15 record. Their only win was in week 15 when they won by a single point. The second team to replicate this feat was the 2016 Cleveland Browns, who, as mentioned above, went winless the following season.
7 games or fewer
Arena football
The previously shorter length of seasons in arena football made imperfect seasons quite possible. The following teams went through an Arena Football League or a National Arena League season without winning a game:
In 2001, the Columbus Wardogs of AF2, the minor league of the AFL, made history becoming the first American football team to go 0–16.
United Football League
The United Football League had one winless season. In their inaugural season, the 2009 New York Sentinels lost all six of their games. The team, which was a traveling team that played games in Hartford, Long Island and New Jersey (and had intended to play a game in New York City but backed out), fired its head coach and settled permanently in Hartford to become the Hartford Colonials. Under the UFL's double round robin format, only one team could finish any particular season entirely with losses, since every team played each other at least twice.
World League of American Football
The 1991 inaugural season of the World League of American Football saw the Raleigh-Durham Skyhawks fold after losing all ten of their regular-season games. The following year, the WLAF replaced that franchise with the Ohio Glory who almost met the same fate but managed one win in their lone season.