Single-A, formerly known as Class A and sometimes as Low-A, is the fourth-highest level of play in

Minor League Baseball Minor League Baseball (MiLB) is a professional baseball organization below Major League Baseball (MLB), constituted of teams affiliated with MLB clubs. It was founded on September 5, 1901, in response to the growing dominance of the National Le ...

in the United States, below Triple-A, Double-A, and

High-A High-A, officially Class High-A, formerly known as Class A-Advanced, and sometimes abbreviated "A+" in writing, is the third-highest level of play in Minor League Baseball in the United States and Canada, below Triple-A (baseball), Triple-A and D ...

. There are 30 teams classified at the Single-A level, one for each team in

Major League Baseball Major League Baseball (MLB) is a professional baseball league composed of 30 teams, divided equally between the National League (baseball), National League (NL) and the American League (AL), with 29 in the United States and 1 in Canada. MLB i ...

(MLB), organized into three leagues: the

California League The California League is a Minor League Baseball league that operates in California. Having been classified at various levels throughout its existence, it operated at Class A-Advanced from 1990 until its demotion to Single-A following Major Leagu ...

Carolina League The Carolina League is a Minor League Baseball league which has operated along the Atlantic Coast of the United States since 1945. Having been classified at various levels throughout its existence, it operated at Class A-Advanced from 1990 unti ...

, and

Florida State League The Florida State League (FSL) is a Minor League Baseball league based in the state of Florida. Having been classified at various levels throughout its existence, it operated at Class A-Advanced from 1990 until its demotion to Single-A following ...

History

Class A was originally the highest level of

, beginning with the earliest classifications, established circa 1890. Teams within leagues at this level had their players' contracts protected and the players were subject to

reserve clause The reserve clause, in North American professional sports, was part of a player contract which stated that the rights to players were retained by the team upon the contract's expiration. Players under these contracts were not free to enter into ano ...

s. When the National Association of Professional Baseball Leagues – the formal name of Minor League Baseball – was founded in 1901, Class A remained the highest level, restricted to leagues with cities that had an aggregate population of over a million people. Entering the 1902 season, the only Class A leagues were the Eastern League and the Western League—both leagues had eight teams, in cities such as

Toronto, Ontario Toronto ( , locally pronounced or ) is the List of the largest municipalities in Canada by population, most populous city in Canada. It is the capital city of the Provinces and territories of Canada, Canadian province of Ontario. With a p ...

;

Buffalo, New York Buffalo is a Administrative divisions of New York (state), city in the U.S. state of New York (state), New York and county seat of Erie County, New York, Erie County. It lies in Western New York at the eastern end of Lake Erie, at the head of ...

;

Worcester, Massachusetts Worcester ( , ) is the List of municipalities in Massachusetts, second-most populous city in the U.S. state of Massachusetts and the list of United States cities by population, 113th most populous city in the United States. Named after Worcester ...

;

Omaha, Nebraska Omaha ( ) is the List of cities in Nebraska, most populous city in the U.S. state of Nebraska. It is located in the Midwestern United States along the Missouri River, about north of the mouth of the Platte River. The nation's List of United S ...

;

Denver, Colorado Denver ( ) is a List of municipalities in Colorado#Consolidated city and county, consolidated city and county, the List of capitals in the United States, capital and List of municipalities in Colorado, most populous city of the U.S. state of ...

; and

Peoria, Illinois Peoria ( ) is a city in Peoria County, Illinois, United States, and its county seat. Located on the Illinois River, the city had a population of 113,150 as of the 2020 United States census, 2020 census, making it the List of municipalities in Ill ...

. Leagues operating within less populated areas were classified as Class B, Class C, or Class D. Class A remained the top classification until

Class AA Double-A (officially Class AA) is the second-highest level of play in Minor League Baseball in the United States since 1946, below only Triple-A. There are currently 30 teams classified at the Double-A level, one for each team in Major League B ...

was established in 1912, then remained the second-highest classification until Class A1 was established in 1936. In 1946, the top two levels changed from being Class AA and Class A1 to being

Class AAA Triple-A (officially Class AAA) has been the highest level of play in Minor League Baseball in the United States since 1946. Currently, two leagues operate at the Triple-A level, the International League (IL) and the Pacific Coast League (PCL). ...

and AA, with Class A remaining the third-highest level, above Classes B through D. Class A in 1946 consisted of the Eastern League and the original

South Atlantic League The South Atlantic League, often informally called the Sally League, is a Minor League Baseball league with teams predominantly in states along the Atlantic coast of the United States from New York to Georgia. A Class A league for most of its h ...

(or "Sally League"), with teams in communities such as

Vancouver, British Columbia Vancouver is a major city in Western Canada, located in the Lower Mainland region of British Columbia. As the List of cities in British Columbia, most populous city in the province, the 2021 Canadian census recorded 662,248 people in the cit ...

;

Colorado Springs, Colorado Colorado Springs is the most populous city in El Paso County, Colorado, United States, and its county seat. The city had a population of 478,961 at the 2020 United States census, 2020 census, a 15.02% increase since 2010 United States Census, 2 ...

;

Charlotte, North Carolina Charlotte ( ) is the List of municipalities in North Carolina, most populous city in the U.S. state of North Carolina and the county seat of Mecklenburg County, North Carolina, Mecklenburg County. The population was 874,579 at the 2020 United ...

;

Scranton, Pennsylvania Scranton is a city in and the county seat of Lackawanna County, Pennsylvania, United States. With a population of 76,328 as of the 2020 United States census, 2020 census, Scranton is the most populous city in Northeastern Pennsylvania and the ...

; and

Allentown, Pennsylvania Allentown (Pennsylvania Dutch language, Pennsylvania Dutch: ''Allenschteddel'', ''Allenschtadt'', or ''Ellsdaun'') is a city in eastern Pennsylvania, United States. The county seat of Lehigh County, Pennsylvania, Lehigh County, it is the List o ...

. Class A soon included the Western League (1947–1958),

Central League The or , also known as the for sponsorship reasons, is one of the two professional baseball leagues that constitute Nippon Professional Baseball in Japan. The winner of the league championship plays against the winner of the Pacific League i ...

(1948–1951) and

Western International League The Western International League was a mid- to higher-level minor league baseball circuit in the Pacific Northwest United States and western Canada that operated in 1922, 1937 to 1942, and 1946 to 1954. In 1955, the Western International League ...

(1952–1954). The Western International League became the Class B

Northwest League The Northwest League is a Minor League Baseball league that operates in the Northwestern United States and Western Canada. A Class A Short Season league for most of its history, the league was promoted to High-A as part of Major League Baseba ...

in 1955, and the Western and Central loops folded. The hierarchy of Triple-A through Class D continued until Minor League Baseball restructured in 1963, at which time Classes B through D were abolished, with existing leagues at those levels reassigned into Class A, while the South Atlantic League (renamed as the Southern League) and Eastern League ascended to Double-A. In 1965, a

Class A Short Season Class A Short Season (officially Short-Season A) was a level of play in Minor League Baseball in the United States from 1965 through 2020. In the hierarchy of minor league classifications, it was below Triple-A, Double-A, Class A-Advanced (crea ...

designation was created, for teams playing June–September schedules, primarily meant for new players acquired via the amateur draft. The

Class A-Advanced High-A, officially Class High-A, formerly known as Class A-Advanced, and sometimes abbreviated "A+" in writing, is the third-highest level of play in Minor League Baseball in the United States and Canada, below Triple-A (baseball), Triple-A and D ...

designation was established in 1990, between Class A and Double-A in the minor league hierarchy. Class A and Class A Short Season were considered independent classifications, with Class A having "Full-Season" and Advanced sub-classifications, per the rules governing baseball's minor leagues. The overall hierarchy was: # Triple-A # Double-A # Class A-Advanced # Class A ("Full-Season A") # Class A Short Season ("Short-Season A") #

Rookie league Minor League Baseball (MiLB) is a professional baseball organization below Major League Baseball (MLB), constituted of teams affiliated with MLB clubs. It was founded on September 5, 1901, in response to the growing dominance of the National L ...

Entering the 2020 minor league season (which was not played due to the

COVID-19 pandemic The COVID-19 pandemic (also known as the coronavirus pandemic and COVID pandemic), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), began with an disease outbreak, outbreak of COVID-19 in Wuhan, China, in December ...

), Class A consisted of the

Midwest League The Midwest League is a Minor League Baseball league established in 1947 and based in the Midwestern United States. A Class A league for most of its history, the league was promoted to High-A as part of Major League Baseball's 2021 reorganizat ...

and

(a newer "Sally League", which been formed in 1963 as the

Western Carolinas League The Western Carolinas League was a Class D level (1948–52; 1960–62) and a low Class A level (1963–79) full-season league in American minor league baseball. The Western Carolinas League changed its name prior to the 1980 season and has been ...

). Prior to the 2021 season, MLB restructured the minor leagues, eliminating Class A Short Season and discontinuing the use of all historical league names within Minor League Baseball. The Midwest League and South Atlantic League were reclassified as "High-A" leagues, and operated during 2021 as

High-A Central The Midwest League is a Minor League Baseball league established in 1947 and based in the Midwestern United States. A Class A league for most of its history, the league was promoted to High-A as part of Major League Baseball's 2021 reorganizati ...

and

High-A East The South Atlantic League, often informally called the Sally League, is a Minor League Baseball league with teams predominantly in states along the Atlantic coast of the United States from New York to Georgia. A Class A league for most of its hi ...

, respectively. They were replaced at the Class A level by three "Low-A" leagues:

Low-A West The California League is a Minor League Baseball league that operates in California. Having been classified at various levels throughout its existence, it operated at Class A-Advanced from 1990 until its demotion to Single-A following Major Leagu ...

, Low-A East, and

Low-A Southeast The Florida State League (FSL) is a Minor League Baseball league based in the state of Florida. Having been classified at various levels throughout its existence, it operated at Class A-Advanced from 1990 until its demotion to Single-A following ...

. These leagues had historically been known as the

, and

, respectively, and had previously operated at the Class A-Advanced level. These three leagues operated with Low-A naming for the 2021 season. Following MLB's acquisition of the rights to the names of the historical minor leagues, MLB announced on March 16, 2022, that the leagues would revert to their prior names, effective with the 2022 season. MLB also discontinued use of "Low-A" in favor of Single-A.

Current teams

Florida State League

Carolina League

California League

Playoffs

On June 30, 2021, Minor League Baseball announced that the top two teams in each league (based on full-season

winning percentage In sports, a winning percentage or Copeland score is the fraction of games or matches a team or individual has won. The statistic is commonly used in standings or rankings to compare teams or individuals. It is defined as wins divided by the to ...

, and regardless of division) would meet in a best-of-five postseason series to determine league champions.

References

External links

* {{California League Minor league baseball Carolina League Florida State League California League