2011 Major League Baseball postseason

The 2011 Major League Baseball postseason was the playoff tournament of Major League Baseball for the 2011 season. The winners of the Division Series would move on to the League Championship Series to determine the pennant winners that face each other in the World Series. This was the last postseason to feature the 8-team format, as next season a new League Wild Card Game was introduced as the new opening round of the postseason, as well as the last time that two teams from the same division could not face each other in the opening round.

In the American League, the New York Yankees returned for the sixteenth time in the past seventeen years, the Texas Rangers returned for the second straight year, the Detroit Tigers returned for the first time since 2006, and was the first of four consecutive appearances by the Tigers. The Tampa Bay Rays returned for the third time in four years.

In the National League, the St. Louis Cardinals returned for the eighth time in the past twelve years, the Milwaukee Brewers made their second appearance in the past four years, the Philadelphia Phillies returned for the fifth straight time, and the Arizona Diamondbacks returned for the first time since 2007.

The postseason began on September 30, 2011, and ended on October 28, 2011, with the Cardinals defeating the Rangers in seven games in the 2011 World Series. It was the Cardinals' 11th title in franchise history, tying the NHL's Detroit Red Wings for the sixth most championship wins in North American sports.

Playoff seeds
The following teams qualified for the postseason:

American League

 * 1) New York Yankees – AL East champions, AL best record, 97–65
 * 2) Texas Rangers – AL West champions, 96–66
 * 3) Detroit Tigers – AL Central champions, 95–67
 * 4) Tampa Bay Rays – AL Wild Card qualifier, 91–71

National League

 * 1) Philadelphia Phillies – NL East champions, NL best record, MLB best record, 102–60
 * 2) Milwaukee Brewers – NL Central champions, 96–66
 * 3) Arizona Diamondbacks – NL West champions, 94–68
 * 4) St. Louis Cardinals – NL Wild Card qualifier, 90–72

Playoff bracket
  Note: Two teams in the same division cannot meet in the division series.

(1) New York Yankees vs. (3) Detroit Tigers
† : suspended in the bottom of the second inning due to rain

This was the second postseason meeting between the Yankees and Tigers. They previously met in the 2006 ALDS, which the Tigers won in four games. In a hotly contested five-game series, the Tigers once again defeated the Yankees to return to the ALCS for the second time in six years.

The Yankees unsurprisingly took Game 1 in a blowout win, as the Yankees' offense chased Doug Fister from the mound. In Game 2, the Tigers jumped out to a 4-0 lead and their bullpen stopped a late rally by the Yankees to even the series headed back to Detroit. Delmon Young would propel the Tigers to a one-run victory in Game 3 thanks to a solo home run in the bottom of the seventh that broke a 4-4 tie. Then, the Yankees would blow out the Tigers again in Game 4 to send the series back to the Bronx. However, in Game 5, Fister would redeem himself as he and the Tigers' bullpen fended off a late push by the Yankees to win 3-2 and return to the ALCS.

Both teams would meet again in the 2012 ALCS, which the Tigers won in a sweep before falling in the World Series.

(2) Texas Rangers vs. (4) Tampa Bay Rays
This was the second straight postseason meeting between the Rays and Rangers, and a rematch of last year's ALDS. The Rangers once again defeated the Rays to advance to the ALCS for the second year in a row.

Rays' rookie pitcher Matt Moore pitched seven shutout innings in Game 1 as the Rays blew out the Rangers, 9-0. Game 2 was an offensive shootout which the Rangers won 8-6 to even the series headed to Tampa. In the top of the seventh inning of Game 3, Mike Napoli and Josh Hamilton helped the Rangers come from behind to win by a 4-3 score to take the series lead. The Rangers would win the series in Game 4 thanks to a home run from Ian Kinsler and three more from Adrián Beltré.

This was the last time the Rangers appeared in the ALDS until 2015. Both teams would meet again in the Wild Card round of the 2023 postseason, which the Rangers won in a sweep en route to the World Series.

(1) Philadelphia Phillies vs. (4) St. Louis Cardinals
This was the first postseason meeting between the Cardinals and Phillies. The Cardinals upset the heavily favored Phillies in five games to return to the NLCS for the first time since 2006. Both teams split the first two games at Citizens Bank Park - the Phillies prevailed in an offensive duel in Game 1, while in Game 2, the Cardinals overcame a 4–0 lead to win by one run. Cole Hamels helped lead the Phillies to victory in Game 3, while the Cardinals evened the series in Game 4 to send the series back to Philadelphia. The Cardinals closed out the series with a 1–0 shutout in Game 5 to advance, thanks to a solid pitching performance from ace Chris Carpenter.

(2) Milwaukee Brewers vs. (3) Arizona Diamondbacks
This was the first postseason meeting between the Brewers and Diamondbacks. The Brewers defeated the Diamondbacks in five games to reach their first ever LCS as a member of the National League.

Yovani Gallardo helped lead the Brewers to victory in Game 1 with a solid eight-inning performance. In Game 2, with the game tied at four, the Brewers scored five unanswered runs in the bottom of the sixth to win and go up 2–0 in the series headed to Phoenix. The Diamondbacks blew out the Brewers in Game 3, and won a Game 4 slugfest by a 10–6 score to send the series back to Milwaukee for Game 5. The Brewers would end up defeating the Diamondbacks in extra innings in Game 5 to advance to the NLCS. This was the first playoff series win by the Brewers since the 1982 ALCS, when the team was still in the American League.

(4) Texas Rangers vs. (2) Detroit Tigers
† : postponed from October 9 due to rain

In a highly anticipated series between two teams that were hailed as favorites to make the World Series, the Rangers defeated the Tigers in six games to return to the World Series for the second year in a row.

The Rangers won Game 1 by a narrow 3–2 score, and then Nelson Cruz won Game 2 for the Rangers in extra innings via a walk-off grand slam. The Tigers won Game 3, however the Rangers took Game 4 in an 11-inning contest to go up three games to one. The Tigers sent the series back to Arlington with a victory in Game 5, but were eliminated in a blowout victory in Game 6.

The Tigers would return to the ALCS the following year, sweeping the New York Yankees to return to the World Series. The Rangers would win their next AL pennant in 2023, where they defeated their in-state rival in the Houston Astros in seven games.

(2) Milwaukee Brewers vs. (4) St. Louis Cardinals
This was the first postseason meeting between these two teams since the 1982 World Series, which the Cardinals won in seven games. Just like before, the Cardinals once again defeated the Brewers, this time in six games, to return to the World Series for the first time since 2006.

Game 1 was an offensive slugfest which the Brewers won 9-6, thanks to home runs from Ryan Braun, Prince Fielder and Yuniesky Betancourt. In Game 2, the Cardinals blew out the Brewers to even the series headed to St. Louis. Chris Carpenter and the Cardinals' bullpen would fend off a potential rally by the Brewers as they won 4-3 to take the series lead. In Game 4, Randy Wolf pitched seven solid innings as the Brewers came from behind to win and even the series at two. The Cardinals blew out the Brewers again in Game 5 to take a 3-2 series lead headed back to Milwaukee. The Cardinals would clinch the pennant in another blowout win in Game 6, thanks to home runs from David Freese, Rafael Furcal, and Albert Pujols.

The Brewers would not return to the postseason again until 2018, where they reached the NLCS and lost to the Los Angeles Dodgers in seven games. The Cardinals would win their next and most recent pennant in 2013 against the Los Angeles Dodgers in six games.

(AL2) Texas Rangers vs. (NL4) St. Louis Cardinals
† : Postponed from October 26 due to rain

Considered to be one of the greatest World Series ever played, the Cardinals defeated the Rangers in seven games to win their eleventh championship in franchise history.

Both teams split the first two games at Busch Stadium, and the Cardinals blew out the Rangers 16–7 in Game 3 to take a 2–1 series lead. The Rangers responded by shutting out the Cardinals in Game 4, and then won Game 5 by a 4–2 score to be one win away from their first World Series title. Game 6 was the most memorable contest of the series, in which the Cardinals erased a two-run deficit in the bottom of the 9th inning thanks to a triple by David Freese, then did it again in the 10th. In both innings, the Rangers were one strike away from their first World Series championship, however they could not close out the series, and the Cardinals came back to win thanks to a walk-off home run from Freese in the bottom of the 11th inning. In Game 7, the Rangers again took an early lead in the top of the 1st inning, however the Cardinals would tie the game in the bottom of the first, then scored four more runs in the third, fifth and seventh innings to take the lead for good and secure the title.

With the loss, the Rangers became the first team since the 1991–92 Atlanta Braves to lose in consecutive World Series appearances. The Cardinals would return to the World Series again in 2013, but fell to the Boston Red Sox in six games. The Rangers returned to the postseason again next year, but fell to the Baltimore Orioles in the AL Wild Card Game. They would return to the World Series in 2023, winning the first title in franchise history over the Arizona Diamondbacks in five games.

Broadcasting
This was the fifth postseason under a seven-year U.S. rights agreement with Fox and TBS. TBS primarily aired all Division Series games, with sister network TNT used as an overflow channel. TBS also had the National League Championship Series. Fox televised the American League Championship Series and the World Series.