Bye week

A bye, in sports and other competitive activities, most commonly refers to the practice of allowing a player or team to advance to the next round of a playoff tournament without playing. This is generally the result of having a number of entrants in the competition that is not a power of two (i.e., not 2, 4, 8, 16, etc.); any such tournament must eventually arrive, through elimination, at an odd number of participants at some point, thus necessitating the bye. In large tournaments, sometimes the best-ranked players or teams get a bye in the first round(s), to reward them with less risk of elimination, as well as on the basis (particularly in seeded tournaments) that they would be most likely to eliminate the worst seeds anyway. Byes can be applied equally to single-person competitions and team sports, and well as to single-game eliminations and best-of series eliminations.

In round-robin tournament competitions where there are an odd number of competitors each round, usually just one would get a bye. Thus during no round would all teams be able to play. However, by the completion of the tournament each team would have played the same number of games as well as having sat out for the same number of rounds during the tournament. In a Swiss-system tournament with an odd number of players, one will get a bye each round, but not all players will get a bye.

There are multiple ways or reasons to get byes such as random chance, the opponent is unable to participate, the team gets it due to positive or negative past history, the team is handicapped etc..

Gridiron football

 * In a typical use of the term ", the National Football League rewards two division winners from each of the two conferences which possess the best regular season record with a bye in the playoffs. This is necessitated by the current 12-team playoff structure. Eight is the next lowest power of 2, so four teams must be eliminated in the first week to get down to eight teams.  The NFL is currently the only one of the "Big Four" North American sports leagues to offer playoff byes. (The National Basketball Association and the National Hockey League each allow 16 teams in their postseasons, while Major League Baseball allows 8, and since 8 and 16 are both powers of two, no teams receive byes; however, all these leagues settle their playoff rounds in series rather than single games.)  The CFL also grants a bye to its two division winners, directly to the division finals as four other teams compete in a semi-final week.
 * In both Canadian and American professional football leagues, the term "bye week" refers to any week during the regular season in which a team does not play a game. Each NFL team will have one "bye week" during a normal season; this is placed on the schedule between Week 4 and Week 10. The NFL has used the bye week since 1990 so as to extend the regular season schedule to 17 weeks. In 1993 each NFL team had 2 bye weeks. Traditionally, the Canadian Football League and Arena Football have scheduled byes only in seasons when they have had an odd number of teams in their leagues. However, the CFL introduced a scheduled bye week for its eight teams for the 2007 season.

Australian football codes
In leagues such as Australia's National Rugby League (NRL) where competition points are used to determine standings, the bye also garners points (in the NRL's case, two, equivalent to a win). The Australian Football League also had byes during periods in which the competition consisted of an odd number of teams (such as prior to the admission of the Fremantle Dockers in 1995). In an unusual application of the bye, the AFL finals system employs byes even though the finals consist of eight teams (a power of two). The first round of the finals is not a strict elimination round and uses two byes to reward the top four qualifiers for their performance (the byes are earned in matches between those teams). After the second round, four teams remain and the system returns to standard single-elimination.