Sports bye

A bye is a special privilege given to a team in the initial rounds because of which it gets exempted from playing in the first round and directly enters the second round. In knock-out (single-elimination) tournaments, if the number of participants is not a power of two (e.g. 16 or 32), one of the methods used to make a working bracket are byes which automatically move certain participants into a later round without requiring them to compete in an earlier one. Although it may not be necessary based on the format of the tournament, other types of eliminator tournaments may also include a bye for other reasons, such as to reward the best ranked participant(s).

In round-robin tournaments where there are an odd number of competitors, usually one competitor gets a bye in each round, as it is impossible for all competitors to play in the same round. However, over the whole tournament, each team plays the same number of games as well as sitting out for the same number of rounds during the tournament.

Similar to the round-robin context, in leagues where almost all teams play on the same days in regular-season play, a team that does not play on a given day is said to be on bye. In sports that are played weekly, especially football, a team that does not play at all during a given week is said to be on its "bye week". (This definition is chiefly U.S.)

In a standard single-elimination tournament, each round has half the number of teams as the preceding round. Thus the finals will have two, the semi-finals will have four, the quarter finals will have eight, etc. Thus tournaments with competitors numbering a power of two can have a standard bracket in which all teams are paired up with the loser of each match eliminated and the winner moving on to the next round until only one champion remains.

However, if the number of teams is not a power of two, a simple elimination tournament will eventually produce a round with an odd number of teams (if the number is not odd to start with). For example, a tournament of nine teams could only have four matches in the first round, while a simple tournament of ten teams would produce a second round with five teams, meaning only four matches could occur.

One method of allowing more teams to compete in tournaments is to give one or more teams a bye which allows them to automatically pass to a subsequent round without competing. Most commonly the teams with the highest ranking going into the tournament are given a bye to the second round, as it is generally seen as an advantage to be assured entry into a later round. In the NFL playoffs, for example, the top two division-leaders in each conference are given byes to the second round. The Canadian Football League (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 other tournaments where teams are unranked, random draw may be used to determine the byes.

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Wikipedia