The sport of baseball has several professional leagues throughout the world; that is, leagues where the players are paid to play.
North America
Major League Baseball in North America consists of the National League and the American League. Historically, teams in one league never played teams in the other until the World Series, in which the champions of the two leagues played against each other; this changed in 1997 with the advent of interleague play.
In addition to the major leagues, many North American cities and towns feature minor league teams. An organization officially styled Minor League Baseball, formerly the National Association of Professional Baseball, oversees nearly all minor league baseball in the United States and Canada. The minor leagues are divided into classes AAA, AA, A, and rookie league. These minor-league teams are affiliated with major league teams, and serve to develop young players and rehabilitate injured major leaguers. The Mexican League is a Minor League Baseball member league that operates without affiliations to major league teams.
There are also a number of non-Minor League Baseball leagues that are not directly affiliated with Major League Baseball. Four of these, the American Association, the Atlantic League, the Frontier League, and the Pioneer League, have been deemed MLB Partner Leagues. They do not field players under MLB contract like MiLB teams do, but they cooperate with MLB by testing rules changes. Other, wholly independent leagues include the United Shore Professional Baseball League and the Pecos League.
During the late 19th and early 20th centuries, African-American players were barred from playing the major leagues, though several did manage to play by claiming to be Cubans or Indians. As a result, a number of parallel Negro Leagues were formed. However, after Jackie Robinson began playing with the major-league Brooklyn Dodgers in 1947, the Negro Leagues gradually faded. The process of integration did not go entirely smoothly; there were some ugly incidents, including pitchers who would try to throw directly at an African-American player's head. Now, however, baseball is fully integrated, and there is little to no racial tension between teammates.
Between 1943 and 1954, the All-American Girls Professional Baseball League fielded teams in several Midwestern towns.
Japan
Japan has had professional baseball since the 1930s. Currently, it consists of two leagues, the Central League and the Pacific League, each with six teams.
Korea
South Korea has had professional baseball since 1982. There are 8 teams in Korea Professional Baseball league.(Korea Baseball Organization)
Colombia
- Colombian Professional Baseball League
Cuba
- Cuban League (defunct)
Dominican Republic
- Dominican Winter Baseball League
Rest of the world
Professional leagues exist in Taiwan, the Dominican Republic, and Latin America, the Netherlands, Italy (from 1948), Germany (from 1951), Australia, and the rest of Europe.
| Professional Baseball | |
| Americas | |
| Major League Baseball | American League • National League |
| Minor League Baseball | *Triple A : International League • Mexican League • Pacific Coast League
|
| Mexican League Affilates | *Double A : Nothern Mexico League
|
| Winter | *Affilliated: Arizona Fall League • Dominican Winter Baseball League • Mexican Pacific League • Parallel Leaguee • Venezuelan Professional Baseball League
|
| Defunct | *Major :National Association • American Association • Union Association • Player's League •
Federal League • Negro League baseball • All-American Girls Professional Baseball League • Continental League • Cuban League • National Association of Base Ball Players
|
| Asia | |
| Japan | Nippon Professional Baseball : Central League • Pacific League
|
| South Korea | Korea Professional Baseball
|
| Taiwan | Chinese Professional Baseball League |
| China | China Baseball League |
| Defunct | Japanese Baseball League • Taiwan Major League • Israel Baseball League |
| Europe | |
| Italy | Italian Baseball League |
| Netherlands | Honkbal Hoofdklasse |
| Oceania | |
| Australia | Australian Baseball |
| Defunct | Australian Baseball (1989-1999) • International Baseball League of Australia • Hawaii Winter Baseball |