MLB

The National League (NL) was formed under Chicago businessman William A. Hulbert with clubs in eight cities. It established common player-contract and administrative rules and became part of the later major-league system.⁠[1]

The American League (AL) emerged as a rival in 1901, competing with the National League for players and spectators. The leagues made peace in 1903, when Pittsburgh and the Boston AmericansBoston Red SoxThe Boston Red Sox are a Major League Baseball (MLB) team in the American League East. Their headquarters and home ballpark, Fenway Park, are in Boston, Massachusetts. The club is part of Fenway Sports Group. Founded in 1901, it has won nine World Series championships.Open the full entry contested the first modern World Series. Boston won in eight games. The series paused in 1904 and resumed in 1905.⁠[2]

Following the Black Sox scandal, Kenesaw Mountain Landis became baseball’s first commissioner with broad disciplinary authority. Despite their criminal acquittal, he expelled eight implicated players from professional baseball in 1921. His tenure also perpetuated baseball’s racial segregation.⁠[3][4]

Jackie Robinson debuted for the Brooklyn DodgersLos Angeles DodgersThe Los Angeles Dodgers are a professional baseball club in Los Angeles, playing in Major League Baseball’s National League at Dodger Stadium.Open the full entry, becoming the first African American to play in the American or National League in the twentieth century. After playing for the Montreal Royals in 1946, his arrival with the Dodgers helped advance major-league integration.⁠[5]

The Dodgers moved from Brooklyn to Los Angeles, and the Giants from New York to San Francisco. These relocations brought major-league clubs to the Pacific coast, extending a map previously centered on the Northeast and Midwest.⁠[6]

The MLB Players Association became a labor union in 1966, with Marvin Miller as its first full-time executive director. Its first collective bargaining agreement with the clubs followed in 1968, increasing players’ role in negotiating employment conditions.⁠[7]

Curt Flood challenged a trade made without his consent in 1969, ultimately losing his lawsuit. In 1975, arbitrator Peter Seitz declared Andy Messersmith and Dave McNally free agents, marking a major break with the reserve-clause system.⁠[8]

Players went on strike on August 12, 1994, with disputes including the owners’ proposed salary cap. The remaining regular season and World Series were canceled. Following a court injunction in March 1995, the strike ended on April 2; that season used a 144-game schedule.⁠[9]

The postseason expanded to 12 teams in 2022.⁠[10]

A pitch timer was introduced in 2023.⁠[11]

MLB introduced the Automated Ball-Strike Challenge System (ABS), using Hawk-Eye and Statcast technology to review disputed calls. Only batters, pitchers and catchers may initiate challenges. Each team receives two challenges per game and loses one only when unsuccessful. In extra innings, each team has at least one challenge available per inning.⁠[12]

The AL and NL each have East, Central and West divisions.⁠[13]

Each club is scheduled for 162 regular-season games. In each league, three division champions and three Wild Card teams qualify for the postseason; the two leading division champions receive first-round byes. Wild Card Series are best-of-three, Division Series best-of-five, and League Championship Series and the World Series best-of-seven.⁠[14]

The players’ association represents players on 30 major-league clubs. The current major-league collective bargaining agreement expires on December 1, 2026 and governs pay, benefits and other working conditions.⁠[7]

MLB: Official website: https://www.mlb.com/ (opens in a new window).⁠[110]

MLB: X: https://x.com/MLB (opens in a new window).⁠[111]

MLB: Instagram: https://www.instagram.com/mlb/ (opens in a new window).⁠[112]

MLB: Facebook: https://www.facebook.com/mlb (opens in a new window).⁠[113]

MLB: YouTubeYouTubeYouTube is Google’s video-sharing and creator platform, founded in 2005 by Steve Chen, Chad Hurley, and Jawed Karim and acquired by Google in 2006. Built around video uploading, viewing, and creator earnings, the platform has developed Shorts, YouTube Music, Premium, YouTube TV, and products for children, and is headquartered in San Bruno, California, United States.Open the full entry: https://www.youtube.com/@MLB (opens in a new window).⁠[114]