League Division Series

The Division Series (also known as the League Division Series) is the quarterfinal round of the Major League Baseball playoffs. As with any quarterfinal in a best of tournament, a total of four series are played in this round, two each for both the American League and the National League.

The first use of the term "Division Series" dates from 1981, when due to a mid-season players' strike, that season was divided into two halves, with the winners of each half from each division playing one another in a best-of-five series to decide which team would represent that division in the League Championship Series (this format being common in minor-league baseball). But because the two halves of the season were independent of one another, the winner of the first half had no real incentive to try to win the second half as well (since, unlike in the minor leagues, if the same team did win both halves it was not given a bye into the next round), and a team that won neither half could have actually had the best overall record in the division; indeed, the latter actually occurred, as the Cincinnati Reds and the St. Louis Cardinals had the two best won-lost records (in both halves of the season combined) in the National League (and at the time were in separate divisions, the Reds in the West and the Cardinals in the East), with the Reds having the best overall winning percentage in all of Major League Baseball, yet neither advanced to the playoffs because they finished second in their divisions in each half. Until 2012, when the rules changed, this was the only Division Series which actually consisted of teams from the same division playing each other.

In 1993, the owners approved to institute the Division Series, given the fact that three of the four series went to a game 5. Originally the format called for the top team in the AL East to play the 2nd place team on the AL West and vice versa. In 1994, both the National League and the American League realigned, with the number of divisions in both increasing from two to three (with fewer teams in each). At the same time, the number of teams qualifying for baseball's postseason was doubled, from four to eight; henceforth the three first-place teams from each league's divisions would reach the postseason, along with one wild card team from each league (the latter being the second-place finisher with the best regular-season record). However, this expanded playoff format would not return until the following year, because a players' strike, which began on August 12, 1994, led to the cancellation of that season's playoffs and World Series (and caused the 1995 regular season to have 18 fewer games for each team than normal).

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