The following is a timeline of franchise evolution in Major League Baseball. The histories of franchises in the National Association of Base Ball Players (NABBP), National Association of Professional Base Ball Players (NA), Union Association (UA), and American Association (AA) before they joined the National League (NL) are also included. In 1900 the minor league Western League renamed itself the American League (AL). All of the 1899 Western League teams were a part of the transformation with the Saint Paul Apostles moving to Chicago and to play as the White Stockings. In 1901 the AL declared itself a Major League. For its inaugural major league season the AL dropped its teams in Indianapolis, Buffalo and Minneapolis and replaced them with franchises in Boston, Philadelphia, and Baltimore and the Kansas City Blues moved to Washington to play as the Senators.
In 2020, Major League Baseball designated the following seven Negro Leagues from 1920–1948 as major leagues:[1] Negro National League I (NNL), Eastern Colored League (ECL), American Negro League (ANL), East–West League (EWL), Negro Southern League (NSL), Negro National League II (NNL), and Negro American League (NAL).
The timeline has not yet been fully updated to reflect that designation (in addition, the timeline does not include any non-National League/American League teams which existed at the Major League level from 1876 to 1915).
The History of organizational changes section includes all leagues and which have been designated as major league by MLB, listed chronologically by founding date:
The first line is the formation of the National League in 1876, and the second is the transformation of the American League to a major league in 1901. The third line is the beginning of the expansion era in 1961.
World Series championships are shown with a "*", National League Pennants before the World Series are shown with a "^", and American League Pennants before the World Series "#". No World Series was played in 1904, so the pennant winners for each league are indicated. Due to the 1994-95 Major League Baseball strike, there were no pennant winners or World Series in 1994, so this year is left blank.
The NL was established with eight teams.
Only season in NL § |
Boston Red Caps | Louisville Grays | |
Chicago White Stockings | New York Mutuals§ | |
Cincinnati Reds | Philadelphia Athletics§ | |
Hartford Dark Blues | St. Louis Brown Stockings |
Team folded after this season ^ |
Boston Red Caps | Cincinnati Reds | |
Brooklyn Hartfords^ | Louisville Grays^ | |
Chicago White Stockings | St. Louis Brown Stockings^ |
First season in NL * | Only season in NL § |
Boston Red Caps | Indianapolis Blues§ | |
Chicago White Stockings | Milwaukee Grays§ | |
Cincinnati Reds | Providence Grays* |
First season in NL * | Only season in NL § | Team disbanded after this season ^ |
Boston Red Caps | Cleveland Blues* | |
Buffalo Bisons* | Providence Grays | |
Chicago White Stockings | Syracuse Stars§ | |
Cincinnati Reds^ | Troy Trojans* |
First season in NL * | Only season in NL § |
Boston Red Caps | Cleveland Blues | |
Buffalo Bisons | Providence Grays | |
Chicago White Stockings | Troy Trojans | |
Cincinnati Stars§ | Worcester Worcesters* |
First season in NL * |
Boston Red Caps | Detroit Wolverines* | |
Buffalo Bisons | Providence Grays | |
Chicago White Stockings | Troy Trojans | |
Cleveland Blues | Worcester Worcesters |
The AA was established with six teams.
Team folded after this season ^ |
First MLB season * |
First season in AA * | Only season in AA/Folds mid-season § | Last season in AA or NL ^ |
Team moved from the former UA ** | Last season in NL ^ |
First season in NL * | Only season in NL § |
First season in AA * | Team moved from AA ** | Last season in AA ^ |
First season in AA * | Last season in NL ^ |
First season in AA * | Team moved from AA ** | Last season in AA or NL ^ |
Team moved from AA ** | Only season in AA § |
First MLB season * | Only season in MLB § | Last MLB season ^ |
Teams move from the former AA ** |
The Brooklyn Grooms became the Brooklyn Bridegrooms again.
The Chicago Colts became the Chicago Orphans.
Team folded after this season ^ |
Boston Beaneaters | New York Giants | |
Brooklyn Superbas | Philadelphia Phillies | |
Chicago Orphans | Pittsburgh Pirates | |
Cincinnati Reds | St. Louis Cardinals |
The AL was established with eight teams.
Team folded after this season ^ |
First AL season * |
The Chicago White Stockings became the Chicago White Sox.
The Boston Beaneaters became the Boston Doves.
The Boston Americans became the Boston Red Sox.
The Boston Rustlers became the Boston Braves.
The FL folded prior to the season.
The NNL was established with eight teams, the first black baseball league to be designated a major league.
Team withdrew after this season ^^ |
Only season in NNL § | Team folded after this season ^ |
First season in NL * | Only season in NNL § |
Only season in NNL § | Team folded after this season ^ |
First season in NNL or ECL* | Only season in NNL § |
Team folded mid-season ^ | Team withdrew after this season ^^ |
Only season in NNL or ECL, folded mid-season § | Team folded after this season ^ | Last season in NNL, withdrew mid-season ^^ |
Team rejoined from minor league Negro Southern League ** | Only season in NNL § | Last season in NNL or ECL ^ | Team departed after this season ^^ |
First season in MLB * | Only season in NNL or ECL § | Last MLB season ^ |
Team folded after this season ^ | Team independent after this season ^^ |
First season in NNL * | Team folded after this season ^ | Team departed after this season ^^ |
First season in NNL * | Team folded after this season ^ |
Team rejoined MLB ** | Only season in MLB § | Team folded after this season ^ | Team departed after this season ^^ |
First season in NNL * | Team moved from former EWL or NSL ** | Only season in NNL, folded mid-season § | Only season in NNL, joined mid-season §§ | Team folded after this season ^ | Team departed after this season ^^ |
First season in NNL * | Only season in NNL § | Team folded after this season ^ |
First season in NNL * | Team rejoined MLB ** | Only season in NNL § | Team folded after this season ^ | Team departed after this season ^^ |
First season in NNL * | Team departed after this season ^^ |
Team rejoined MLB ** | Only season in NAL § |
First season in NAL * | Team rejoined MLB ** | Only season in NNL § | Team departed after this season ^^ |
Team joined NAL or rejoined NNL ** | Team folded after this season ^ | Team left NNL mid-season ^^ |
Team rejoined NAL ** | Team folded after this season ^ |
Team temporarily folded after this season ^^ |
First season in NAL * | Team folds mid-season ^ |
First season in NAL * | Team folds mid-season ^ |
The Cincinnati Clowns split their home games between Cincinnati, Ohio and Indianapolis, Indiana and became the Cincinnati–Indianapolis Clowns.
The Cincinnati–Indianapolis Clowns stopped playing in Cincinnati, Ohio and permanently played in Indianapolis, Indiana and became the Indianapolis Clowns.
The Brooklyn Dodgers, Cleveland Indians, and St. Louis Browns integrated.
Team has yet to integrate † |
Team has yet to integrate † | Team folded after this season ^ |
Team has yet to integrate † |
The Boston Braves integrated.
Team has yet to integrate † |
The Chicago White Sox integrated.
Team has yet to integrate † |
Team has yet to integrate † |
Team has yet to integrate † |
Team has yet to integrate † |
The Philadelphia Phillies integrated.
Team has yet to integrate † |
Team has yet to integrate † |
1961 expansion team * |
1962 expansion team * |
The Milwaukee Braves moved to Atlanta and became the Atlanta Braves.
The Kansas City Athletics moved to Oakland, California, and became the Oakland Athletics.
1969 expansion team * |
The Seattle Pilots moved to Milwaukee and became the Milwaukee Brewers.
1977 expansion team * |
1993 expansion team * |
MLB realigned to three divisions in each league to accommodate an expanded postseason format with a wild card team (although this new playoff format would not be fully implemented until 1995 due to a work stoppage):
The California Angels became the Anaheim Angels.
1998 expansion team * |
The Tampa Bay Devil Rays became the Tampa Bay Rays.
The Florida Marlins became the Miami Marlins.
With interleague play expanded to occur throughout the season, the Houston Astros transferred to the AL West to accommodate each league with 15 clubs apiece.
The Los Angeles Angels of Anaheim became the Los Angeles Angels.
The Cleveland Indians became the Cleveland Guardians.