The 2005 Major League Baseball season was notable for the league's new steroid policy in the wake of the BALCO scandal, which enforced harsher penalties than ever before for steroid use in Major League Baseball. Several players, including veteran Rafael Palmeiro, were suspended under the new policy. Besides steroids it was also notable that every team in the NL East finished the season with at least 81 wins. Additionally it was the first season featuring a baseball team in Washington, D.C. since the second iteration of the Washington Senators last played there in 1971; the Washington Nationals had moved from Montreal, the first relocation of a team in 33 years and currently the most recent time this has occurred in the majors.
The 2004 Major League Baseball season ended when the Boston Red Sox defeated the St. Louis Cardinals in a four-game World Series sweep. The Red Sox championship ended an 86-year-long drought known as the Curse of the Bambino. The Red Sox were also the first team in MLB history and the third team from a major North American professional sports league ever to come back from a 3–0 postseason series deficit and win. This happened in the ALCS against the New York Yankees.
The 2003 Major League Baseball season ended when the Florida Marlins defeated the New York Yankees in a six-game World Series. The Detroit Tigers set the American League record for losses in a season, with 119, and the Marlins became the first team to win the championship twice as a wild card.
The 2006 Major League Baseball season ended with the National League's St. Louis Cardinals winning the World Series with the lowest regular-season victory total (83) in a fully-played season in major league history. The Atlanta Braves failed to qualify for the postseason for the first time since 1990. Individual achievements included Barry Bonds who, despite questions surrounding his alleged steroid use and involvement in the BALCO scandal, surpassed Babe Ruth for second place on the career home runs list. The American League continued its domination at the All-Star Game by winning its fourth straight game, and ninth of the prior 10 contests.
The 2007 Major League Baseball season began on April 1 with a rematch of the 2006 National League Championship Series; the St. Louis Cardinals and New York Mets played the first game of the season at Busch Stadium in St. Louis, Missouri, which was won by the Mets, 6–1. The regular season concluded with seven teams entering the postseason who had failed to reach the 2006 playoffs including all National League teams, with only the New York Yankees returning; a dramatic one-game playoff between the Colorado Rockies and San Diego Padres; and the largest September collapse for a leading team in baseball history, with the Mets squandering a 7-game lead with 17 to play, losing on the final day of the regular season, and the Philadelphia Phillies capturing the National League East for the first time since 1993. The season ended on October 28, with the Boston Red Sox sweeping the World Series over the Rockies, four games to zero.
The 2001 Major League Baseball season finished with the Arizona Diamondbacks defeating the New York Yankees in seven games for the World Series championship. The September 11 terrorist attacks on New York and Washington, D.C. pushed the end of the regular season from September 30 to October 7. Because of the attacks, the World Series was not completed until November 4. The 2001 World Series was the first World Series to end in November.
The 2002 Major League Baseball season finished with two wild-card teams contesting the World Series; the Anaheim Angels defeated the San Francisco Giants in seven games for the World Series championship. It was the first title in Angels team history. This was the first season for MLB.tv.
The 1997 Major League Baseball season was the inaugural season for Interleague play, as well as the final season in the American League for the Milwaukee Brewers before moving to the NL the following season. The California Angels changed their name to the Anaheim Angels. The Florida Marlins ended the season as the World Champions defeating the Cleveland Indians in a seven-game World Series, four games to three.
The 1995 Major League Baseball season was the first season to be played under the expanded postseason format, as the League Division Series (LDS) was played in both the American and National leagues for the first time, since the 1981 strike-split season. However, due to the 1994–95 Major League Baseball strike which carried into the 1995 season, a shortened 144-game schedule commenced on April 25, when the Florida Marlins played host to the Los Angeles Dodgers.
The 1999 Major League Baseball season ended with the New York Yankees sweeping the Atlanta Braves in the World Series.
The 1996 Major League Baseball season was the final season of league-only play before the beginning of interleague play the following season. The season ended with the New York Yankees defeating the defending champion Atlanta Braves in six games for the World Series title, the Yankees' first championship since 1978. The record for most home runs hit in an MLB regular season, set at 4,458 in 1987, was broken, as the AL and NL combined to hit 4,962 home runs. Only 196 shutouts were recorded in the 2,266 MLB regular-season games. This was the first season in the Divisional Series era to be played to the full 162 games, as the 1994–95 player's strike caused the first two seasons of the era to be abbreviated.
The 1992 Major League Baseball season saw the Toronto Blue Jays defeat the Atlanta Braves in the World Series, becoming the first team outside the United States to win the World Series.
The 1991 Major League Baseball season saw the Minnesota Twins defeat the Atlanta Braves for the World Series title, in a series where every game was won by the home team.
The 1990 Major League Baseball season saw the Cincinnati Reds upset the heavily favored Oakland Athletics in the World Series, for their first title since 1976.
The 1989 Major League Baseball season saw the Oakland Athletics win their first World Series title since 1974.
The 1986 Major League Baseball season saw the New York Mets win their second World Series title, their first since 1969.
The 1987 Major League Baseball season ended with the American League Champion Minnesota Twins winning the World Series over the National League Champion St. Louis Cardinals, four games to three, as all seven games were won by the home team.
The 1983 Major League Baseball season ended with the Baltimore Orioles defeating the Philadelphia Phillies in the fifth game of the World Series. Rick Dempsey was named MVP of the Series. The All-Star Game was held on July 6 at Comiskey Park; the American League won by a score of 13–3, with California Angels outfielder Fred Lynn being named MVP. As of 2024 this remains the most recent season where no player hit for the cycle in a game.
The 1977 Major League Baseball season saw the American League (AL) having its third expansion, as the Seattle Mariners and Toronto Blue Jays began play, with Seattle returning to the MLB fold after a seven-year absence when the Pilots relocated to Milwaukee to become the Brewers. However, the National League (NL) did not expand, remaining at 12 teams compared to the AL's 14, until the Colorado Rockies and Florida Marlins joined the NL in 1993.
The 2009 Major League Baseball season began on April 5, 2009; the regular season was extended two days for a one-game playoff between the Detroit Tigers and the Minnesota Twins for the American League Central title. The postseason began the next day with the Division Series. The World Series began on October 28, and ended on November 4, with the New York Yankees defeating the Philadelphia Phillies in six games. This was the second time the season was completed in November. The only other occasion was the 2001 World Series, because of the delaying of the end of that season due to the September 11 attacks as November baseball would be guaranteed when Game 4 was played on Sunday, November 1. Had the 2009 World Series gone the full seven games, Game 7 would've been played on November 5, the latest date ever scheduled for a World Series game. It became the latest date for a World Series game in 2022. The American League champion had home field advantage for the World Series by virtue of winning the All-Star Game on July 14 at Busch Stadium in St. Louis, Missouri, 4–3. In addition, the annual Civil Rights Game became a regular season game, and was played June 20 at Great American Ball Park in Cincinnati, Ohio, when the host Cincinnati Reds lost to the Chicago White Sox in an interleague game, 10–8. Both teams wore replicas of their 1965 uniforms in the contest.
