In Major League Baseball, the American League Division Series (ALDS) determines which two teams from the American League will advance to the American League Championship Series. The Division Series consists of two concurrent best-of-five series, featuring the three division winners and the winner of the wild-card game.
The Division Series was implemented in 1981 as a result of a midseason strike, with the first place teams before the strike taking on the teams in first place after the strike. After 1993, it was implemented for good when Major League Baseball restructured each league into three divisions, but their next playing was in 1995 due to the cancellation of the 1994 playoffs. In 1981, a split-season format forced the first ever divisional playoff series, in which the New York Yankees won the Eastern Division series over the Milwaukee Brewers (who were in the American League until 1998) in five games while in the Western Division, the Oakland Athletics swept the Kansas City Royals (the only team with an overall losing record to ever make the postseason). The Yankees have currently played in the most division series in history, with fifteen appearances. The Toronto Blue Jays are the only team to have never played in the ALDS and are the last team to win the World Series under the old 4 division format. The Kansas City Royals have yet to play in the ALDS since it became a postseason fixture in 1995.
Determining the matchups 
From 1998 to 2011, the wild-card team has been assigned to play in the division winner with the best winning percentage (outside of their own division) in one series, and the other two division winners meet in the other series. However, if the wild-card team and the division winner with the best record are from the same division, the wild-card team plays the division winner with the second-best record, and the remaining two division leaders play. Beginning with the 2012 season, the wild card team that advances to the Division Series will face the number 1 seed, regardless of whether or not they are in the same division. The two series winners move on to the best-of-seven ALCS. Home field advantage goes to the team with the better regular season record, except for the wild card team, which never receives the home field advantage.
Beginning in 2007, MLB has implemented a new rule to give the team from the league that wins the All-Star Game with the best regular season record a slightly greater advantage. In order to spread out the Division Series games for broadcast purposes, the two ALDS series follow one of two off-day schedules. Starting in 2007, after consulting the MLBPA, MLB has decided to allow the team with the best record in the league that wins the All-Star Game to choose whether to use the seven-day schedule (1-2-off-3-4-off-5) or the eight-day schedule (1-off-2-off-3-4-off-5). The team only gets to choose the schedule; the opponent is still determined by win-loss records.
Initially, the best-of-5 series played in a 2-3 format, with the first two games set at home for the lower seed team and the last three for the higher seed. Since 1998, the series has followed a 2-2-1 format,  where the higher seed team plays at home in Games 1 and 2, the lower seed plays at home in Game 3 and Game 4 (if necessary), and if a Game 5 is needed, the teams return to the higher seed's field. When MLB added a second wild card team in 2012, the Division Series re-adopted the 2-3 format due to scheduling conflicts. It will revert to the 2-2-1 format from 2013 onwards.
Recurring matchups 
||Boston Red Sox vs. Los Angeles Angels of Anaheim
||Red Sox, 3-1
||2004, 2007, 2008, 2009
||New York Yankees vs. Minnesota Twins
||2003, 2004, 2009, 2010
||Cleveland Indians vs. Boston Red Sox
||1995, 1998, 1999
||Texas Rangers vs. New York Yankees
||1996, 1998, 1999
||New York Yankees vs. Oakland Athletics
||New York Yankees vs. Anaheim-LA Angels
||New York Yankees vs. Cleveland Indians
||Texas Rangers vs. Tampa Bay Rays
||Oakland Athletics vs. Minnesota Twins
||Detroit Tigers vs. New York Yankees
ALDS results 
- Team names link to the season in which each team played
See also 
External links