The following is a timeline of franchise evolution in Major League Baseball (MLB).
Background Source:
Note: Team names are given here according to the convention used by The Baseball Encyclopedia, which regularized them into the familiar form of modern team names. However, most teams in the early period had no name, aside from that of the club (as in "Hartford Base Ball Club" or "Athletic Base Ball Club of Philadelphia"), and nicknames like "Beaneaters," "Perfectos" and the many allusions to uniform colors were inventions by the florid sportswriters of the day.According to the National League's 1877 Constitution, the member clubs were given as "Boston B. B. Club, Chicago B. B. Club, Cincinnati B. B. Club, Hartford B. B. Club, Louisville B. B. Club, St. Louis B. B. Club." Constitution and Playing Rules of the National League of Professional Base Ball Clubs. Chicago, A. G. Spalding 1877. The National Association of Base Ball Players (NABBP) was the first organization to govern baseball. The succeeding National Association of Professional Base Ball Players (NA) was then established as the first professional baseball league. In 1876 six clubs from the NA and two independents joined to create the National League (NL). In subsequent years, the following major leagues competed against the NL, but all eventually folded:
American Association (AA) (1882–1891) – eight franchises transferred to the NL, both during and after the AA's existence. Union Association (UA) (1884) – only one franchise joined the NL after the UA disbanded. Players' League (PL) (1890) – none of its franchises joined the NL.
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 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. The Kansas City Blues moved to Washington D.C. to play as the Senators.
Another major league competitor was the Federal League (FL) (1914–1915). However, none of its teams joined either the NL or AL after it disbanded.
In 2020, Major League Baseball designated the following seven Negro leagues from 1920–1948 as major leagues:
Negro National League I (NNL I) (1920–1931) Eastern Colored League (ECL) (1923–1928) American Negro League (ANL) (1929) East–West League (EWL) (1932) Negro Southern League (NSL) (1932) Negro National League II (NNL II) (1933–1948) Negro American League (NAL) (1937–1948)
Timeline
The first line is the formation of the National League (NL) in 1876, and the second is the transformation of the American League (AL) to a major league in 1901. The third line is the beginning of the expansion era in 1961. The fourth line marks the legal merger of the American and National Leagues into a single Major League Baseball in 2000.
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 are shown with a "#". 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 or World Series winners in 1994, so this year is left blank.
Prior to 1876, only teams from the National Association (NA) that established the NL are shown. Between 1876 and 1901, in addition to the NL teams, only American Association (AA) and Union Association (UA) teams that eventually joined the NL are shown. No teams from the Players' League (PL) are shown. Between 1894 and 1901, only teams from the minor league Western League (WL) that established the AL are shown. After 1901, only AL and NL teams are shown. No teams from the Federal League (FL) nor the seven Negro leagues are shown.
1876–1900: Pre-modern Era 1876: Founding of the National League (NL) The NL was established with eight teams.
Only season in NL § + NL teamsBoston Red CapsChicago White StockingsCincinnati RedsHartford Dark Blues Louisville Grays New York Mutuals§ Philadelphia Athletics§ St. Louis Brown Stockings
1877 The New York Mutuals and Philadelphia Athletics were expelled. The Hartford Dark Blues moved to Brooklyn and became the Brooklyn Hartfords.
Team folded after the season ^ + NL teamsBoston Red CapsBrooklyn Hartfords^Chicago White Stockings Cincinnati Reds Louisville Grays^ St. Louis Brown Stockings^
1878 The Brooklyn Hartfords, Louisville Grays, and St. Louis Brown Stockings folded. The Indianapolis Blues, Milwaukee Grays, and Providence Grays joined.
First season in NL * Only season in NL § + NL teamsBoston Red CapsChicago White StockingsCincinnati Reds Indianapolis Blues§ Milwaukee Grays§ Providence Grays*
1879 The Indianapolis Blues and Milwaukee Grays folded. The Buffalo Bisons, Cleveland Blues, Syracuse Stars, and Troy Trojans joined.
First season in NL * Only season in NL § Team disbanded after the season ^ + NL teamsBoston Red Caps Buffalo Bisons*Chicago White Stockings Cincinnati Reds^ Cleveland Blues* Providence Grays Syracuse Stars§ Troy Trojans*
1880 The Syracuse Stars folded. The Cincinnati Reds disbanded and were replaced by the Cincinnati Stars. The Worcester Worcesters joined.
First season in NL * Only season in NL § + NL teamsBoston Red CapsBuffalo BisonsChicago White Stockings Cincinnati Stars§ Cleveland Blues Providence Grays Troy Trojans Worcester Worcesters*
1881 The Cincinnati Stars were expelled because they refused to sign a league-wide pledge to ban alcohol at ballparks. The Detroit Wolverines joined.
First season in NL * + NL teamsBoston Red CapsBuffalo BisonsChicago White StockingsCleveland Blues Detroit Wolverines* Providence Grays Troy Trojans Worcester Worcesters
1882: Establishment of the American Association (AA) The AA was established with six teams.
Team folded after the season ^ + major league teamsNLAA Boston Red Caps Baltimore Orioles Buffalo Bisons Cincinnati Red Stockings Chicago White Stockings Louisville Eclipse Cleveland Blues Philadelphia Athletics Detroit Wolverines Pittsburgh Alleghenys Providence Grays St. Louis Brown Stockings Troy Trojans^ Worcester Worcesters^
1883 The Troy Trojans and Worcester Worcesters folded. The New York Gothams and Philadelphia Quakers joined the NL. The Columbus Buckeyes and New York Metropolitans joined the AA. The Boston Red Caps became the Boston Beaneaters. The new St. Louis Brown Stockings became the St. Louis Browns.
First season in NL or AA * + major league teamsNLAA Boston Beaneaters Baltimore Orioles Buffalo Bisons Cincinnati Red Stockings Chicago White Stockings Columbus Buckeyes* Cleveland Blues Louisville Eclipse Detroit Wolverines New York Metropolitans* New York Gothams* Philadelphia Athletics Philadelphia Quakers* Pittsburgh Alleghenys Providence Grays St. Louis Browns
1884: The Union Association (UA) as a third league The UA was established with eight teams. The Brooklyn Atlantics, Indianapolis Hoosiers, Toledo Blue Stockings, and Washington Nationals joined the AA. The Altoona Mountain Citys folded early-season and were replaced by the Kansas City Cowboys. The Washington Nationals from the AA folded mid-season and were replaced by the Richmond Virginians from Minor League Baseball. The Philadelphia Keystones folded mid-season and were replaced by the Wilmington Quicksteps from Minor League Baseball. The Quicksteps then folded late-season and were replaced by the Milwaukee Brewers, also from Minor League Baseball. The Chicago Browns moved to Pittsburgh and became the Pittsburgh Stogies, who folded late-season and were replaced by the St. Paul Saints.
First season in AA * Only season in AA/Folds mid-season § Last season in AA or NL ^ + major league teamsNLAAUA Boston Beaneaters Baltimore Orioles Altoona Mountain Citys§ Buffalo Bisons Brooklyn Atlantics* Baltimore Monumentals Chicago White Stockings Cincinnati Red Stockings Boston Reds Cleveland Blues^ Columbus Buckeyes^ Chicago Browns/Pittsburgh Stogies§ Detroit Wolverines Indianapolis Hoosiers§ Cincinnati Outlaw Reds New York Gothams Louisville Eclipse Kansas City Cowboys Philadelphia Quakers New York Metropolitans Milwaukee Brewers Providence Grays Philadelphia Athletics Philadelphia Keystones§ Pittsburgh Alleghenys St. Louis Maroons Richmond Virginians§ St. Paul Saints St. Louis Browns Washington Nationals Toledo Blue Stockings§ Wilmington Quicksteps§ Washington Nationals§
1885: Back to two leagues The UA disbanded. The St. Louis Maroons from the UA joined the NL. The Cleveland Blues, Columbus Buckeyes, Indianapolis Hoosiers, and Toledo Blue Stockings folded. The Richmond Virginians returned to Minor League Baseball. The New York Gothams became the New York Giants. The Brooklyn Atlantics became the Brooklyn Grays. The Louisville Eclipse became the Louisville Colonels.
Team moved from the former UA ** Last season in NL ^ + major league teamsNLAA Boston Beaneaters Baltimore Orioles Buffalo Bisons^ Brooklyn Grays Chicago White Stockings Cincinnati Red Stockings Detroit Wolverines Louisville Colonels New York Giants New York Metropolitans Philadelphia Quakers Philadelphia Athletics Providence Grays^ Pittsburgh Alleghenys St. Louis Maroons** St. Louis Browns
1886 The Buffalo Bisons transferred to Minor League Baseball. The Providence Grays folded. A new Kansas City Cowboys and Washington Nationals joined the NL.
First season in NL * Only season in NL § + major league teamsNLAA Boston Beaneaters Baltimore Orioles Chicago White Stockings Brooklyn Grays Detroit Wolverines Cincinnati Red Stockings Kansas City Cowboys§ Louisville Colonels New York Giants New York Metropolitans Philadelphia Quakers Philadelphia Athletics St. Louis Maroons Pittsburgh Alleghenys Washington Nationals* St. Louis Browns
1887 The Kansas City Cowboys folded. The St. Louis Maroons moved to Indianapolis and became the Indianapolis Hoosiers. The Pittsburgh Alleghenys transferred to the NL. A new Cleveland Blues joined the AA.
First season in AA * Team moved from AA ** Last season in AA ^ + major league teamsNLAA Boston Beaneaters Baltimore Orioles Chicago White Stockings Brooklyn Grays Detroit Wolverines Cincinnati Red Stockings Indianapolis Hoosiers Cleveland Blues* New York Giants Louisville Colonels Philadelphia Quakers New York Metropolitans^ Pittsburgh Alleghenys** Philadelphia Athletics Washington Nationals St. Louis Browns
1888 The Brooklyn Grays became the Brooklyn Bridegrooms. The New York Metropolitans folded. A new Kansas City Cowboys joined the AA.
First season in AA * Last season in NL ^ + major league teamsNLAA Boston Beaneaters Baltimore Orioles Chicago White Stockings Brooklyn Bridegrooms Detroit Wolverines^ Cincinnati Red Stockings Indianapolis Hoosiers Cleveland Blues New York Giants Kansas City Cowboys* Philadelphia Quakers Louisville Colonels Pittsburgh Alleghenys Philadelphia Athletics Washington Nationals St. Louis Browns
1889 The Detroit Wolverines folded. The Cleveland Blues transferred to the NL and became the Cleveland Spiders. The Columbus Solons joined the AA.
First season in AA * Team moved from AA ** Last season in AA or NL ^ + major league teamsNLAA Boston Beaneaters Baltimore Orioles Chicago White Stockings Brooklyn Bridegrooms Cleveland Spiders** Cincinnati Red Stockings Indianapolis Hoosiers^ Columbus Solons* New York Giants Kansas City Cowboys^ Philadelphia Quakers Louisville Colonels Pittsburgh Alleghenys Philadelphia Athletics Washington Nationals^ St. Louis Browns
1890: The Players' League (PL) as a third league The PL was established with eight teams. The Chicago White Stockings became the Chicago Colts. The Philadelphia Quakers became the Philadelphia Phillies. The Brooklyn Bridegrooms transferred to the NL.