Major League Baseball

Major League Baseball (MLB) is an American-based sports league, considered to be the world's premier professional baseball league. MLB contains 30 professional baseball teams (29 in the United States of America and 1 in Canada), which feature players from many countries around the world. In the United States, MLB is considered an Organisation and Legal Entity.

Overview of leagues and divisions

Major League Baseball teams are divided into two separate "leagues" of 15 teams each: the American League (AL), which began play in 1901, and the older National League (NL), which began in 1876.

Currently, each league is further subdivided into three "divisions" of 5 teams each: East, West, and Central. A complete list of current teams, showing the divisional structure of each league, appears at the end of this article.

Teams

Click on a column header to sort the table by that item.

Team	League	Division	City	Year founded
Baltimore Orioles	American	East	Baltimore, Maryland	1901 (as Milwaukee Brewers)
Boston Red Sox	American	East	Boston, Massachusetts	1901 (as Boston Americans)
New York Yankees	American	East	New York, New York	1903 (as New York Highlanders)
Tampa Bay Rays	American	East	St. Petersburg, Florida	1998 (as Tampa Bay Devil Rays)
Toronto Blue Jays	American	East	Toronto, Ontario	1977
Chicago White Sox	American	Central	Chicago, Illinois	1901 (as Chicago White Stockings)
Cleveland Guardians	American	Central	Cleveland, Ohio	1901 (as Cleveland Blues)
Detroit Tigers	American	Central	Detroit, Michigan	1901
Kansas City Royals	American	Central	Kansas City, Missouri	1969
Minnesota Twins	American	Central	Minneapolis-St. Paul, Minnesota	1901 (as Washington Senators)
Los Angeles Angels	American	West	Los Angeles, California	1961
Oakland Athletics	American	West	Oakland, California	1901 (as Philadelphia Athletics)
Seattle Mariners	American	West	Seattle, Washington	1977
Texas Rangers	American	West	Dallas, Texas	1961 (as Washington Senators)
Houston Astros	American	West	Houston, Texas	1962 (as Houston Colt .45s in NL)
Atlanta Braves	National	East	Atlanta, Georgia	1871 (as Boston Red Stockings in the National Association)
Miami Marlins	National	East	Miami, Florida	1993 (as Florida Marlins)
New York Mets	National	East	New York, New York	1962
Philadelphia Phillies	National	East	Philadelphia, Pennsylvania	1883 (as Philadelphia Quakers)
Washington Nationals	National	East	Washington, D.C.	1969 (as Montreal Expos)
Chicago Cubs	National	Central	Chicago, Illinois	1876 (as Chicago White Stockings)
Cincinnati Reds	National	Central	Cincinnati, Ohio	1882 (as Cincinnati Red Stockings in the American Association, also played as exhibition team in 1881)
Milwaukee Brewers	National	Central	Milwaukee, Wisconsin	1969 (as Seattle Pilots in AL)
Pittsburgh Pirates	National	Central	Pittsburgh, Pennsylvania	1882 (as Pittsburgh Alleghanys in the American Association)
St. Louis Cardinals	National	Central	St. Louis, Missouri	1882 (as St. Louis Brown Stockings in the American Association)
Arizona Diamondbacks	National	West	Phoenix, Arizona	1998
Colorado Rockies	National	West	Denver, Colorado	1993
Los Angeles Dodgers	National	West	Los Angeles, California	1884 (as Brooklyn Atlantics in the American Association)
San Diego Padres	National	West	San Diego, California	1969
San Francisco Giants	National	West	San Francisco, California	1883 (as New York Gothams)

NOTE: Contents of the above table is from this template.

History

Early History(1871-1903)

The roots of Major League Baseball go back to 1871 when the National Association of Professional Baseball Clubs was founded, eventually leading to the National League that we know today in 1876.

Until the end of the 19th Century, the National League was considered the predominant professional baseball organization, excluding some challengers such as the American Association and the Players League in the 1880s. The turn of the century changed this with a new "Major League" called the American League, which was created from a former minor league called the Western League. Because the National League was created before the American League, the National League is sometimes referred to as the "Senior Circuit", with the American League being the "Junior Circuit".

The two leagues would not recognize each other until 1903 when the two leagues determined a combined champion through a series of games known as the World Series, first conducted intermittently in the 1880s between the champions of the National League and the American Association. The winner of the World Series has been declared the champion of Major League Baseball every year since, excluding 1904 when John T. Brush, the owner of the New York Giants, refused to allow his team to play what he considered to be an inferior opponent, and in 1994, when a labor stoppage between the Players Union and the owners of Major League Baseball forced a cancellation of the series.

The Color Bar

African American players had played alongside white players in the 19th century, the early years of baseball. However, in the modern era, which began in 1901, the Major Leagues barred black players, who competed in their own Negro League. This color bar persisted until 1947 when Jackie Robinson started playing for the Brooklyn Dodgers and forever changed the face of Major League Baseball. While other African Americans joined the majors later in the same season, it would be over two years before Robinson himself shared the field with another African American player.

In July of 1947, in the American League, Larry Doby started playing for the Cleveland Indians and Hank Thompson and Willard Brown both started playing for the St. Louis Browns. Two and one-half seasons later, in July of 1949, Hank Thompson and Monte Irvin started playing for the National League's New York Giants, and Robinson faced his first non-white opponents when the Dodgers and Giants played each other on July 8 of that year.

In 1997, the 50th anniversary of Robinson's debut, his uniform number 42 was retired by all major league teams. (Players already wearing #42 at the time were allowed to continue doing so until they retired.)

Expansion outside the U.S.

In 1969, MLB expanded outside the border of the United States for the first time with the creation of the Montreal Expos. French-language broadcasters had to invent a whole new lexicon to describe the game to fans. The team was popular with fans, both at its first home at Jarry Park Stadium and later at Montreal's Olympic Stadium. However, a player strike in 1994 crippled a season that saw the Expos on top of baseball. The franchise never recovered from that fateful season, regularly seeing some of the lowest attendance in the league at their games. In 2001, the commissioner of baseball, Bud Selig, announced that Major League Baseball would be contracting two teams, one of them being the Montreal Expos. Later, a new collective bargaining agreement between baseball and its players eliminated the possibility of contraction prior to 2006. This forced MLB to seek out different options for the faltering franchise. In 2004, the final season that saw Major League Baseball in Montreal, the team played several of their "home" games in Puerto Rico. Eventually, the league was able to find a buyer for the team, and the franchise was moved to Washington, D.C., changing the team's name to the Nationals

The league further expanded outside of the U.S. with the addition of the Toronto Blue Jays in 1977. Currently, the Blue Jays still reside there.

Inter-league play

Prior to 1997, teams from the two leagues in MLB never met in the regular season. The only time that teams from different leagues would meet would be in the preseason, the World Series, or in exhibition games. The decision to have inter-league games was met with mixed reaction. Some fans thought that the prospect of some of the match-ups, such as the New York Mets, who are in the National League, and the New York Yankees, who play in the American League, was enthralling. Other more traditional fans of the sport felt that the change was unnecessary.

Steroid Era

Over most of the course of Major League Baseball, there were no rules governing the use of performance-enhancing drugs. Public scrutiny arose during the 1998 season when a bottle of androstenedione, an over-the-counter muscle-building supplement, was found in Mark McGwire's locker. In 2002, an article ran in Sports Illustrated in which former San Diego Padres third baseman and former MVP Ken Caminiti admitted to using steroids and speculated that as many as 50% of major league players were doing the same. The MLB Players Association, the players union, steadfastly refused to allow players to be drug tested. As a result, a Senate subcommittee headed by John McCain and Byron Dorgan strongly suggested to MLB Players Association head Donald Fehr enter into an agreement with MLB to allow drug testing. On August 30, 2002, MLB announced its Joint Drug Prevention and Treatment Program. The program was weak and seen as a victory for the player's union, calling only for random drug surveys and anonymity for those tested. However, in December 2003, several prominent baseball players including Barry Bonds and Jason Giambi were called to testify in front of a grand jury investigating BALCO, which was indicted for distributing steroids to professional athletes. The public outcry surrounding the trial forced Major League Baseball to stiffen the policy.

The new policy, which was started during the 2005 MLB season, tested every player at least once per season, with additional random tests throughout the year, and featured a sliding scale of penalties ranging from a 10-game suspension for the first positive test result, up to a full season's suspension for a fourth offense. Further offenses were handled by the commissioner. Also, offenders under the new policy were publicly named, if, after an appealed second test also came back positive.

This policy lasted less than one full year. In November of 2005, the owners and players agreed on a new, even tougher steroid policy. This one allowed for only three offenses. The first resulted in a 50-game suspension, the second in a 100-game suspension, and a third offense would lead to a lifetime suspension from MLB. This policy brought MLB a lot closer to many other sports in terms of how performance-enhancing drugs are handled.

In 2006, Commissioner Bud Selig appointed former U.S. Senator George Mitchell to head an independent investigation into the reported abuse of performance-enhancing drugs. The findings, known as the Mitchell Report, were released to the public on December 13, 2007. The report listed over 70 former and current players who were linked to these drugs, including some of Major League Baseball's premier players.

Notable rule changes

2023: Three new rules

• Timers for batters and pitchers: A 30-second timer is in effect between batters. Between pitches, there is either a 15-second timer when the bases are empty or a 20-second timer if there are one or more runners on base. Violations of the batter timer result in an automatic strike, while violations of the pitcher timer result in an automatic ball. With runners on base, the pitcher timer resets if the pitcher has a disengagement (either attempts a pickoff or steps off the rubber), but a pitcher is limited to just two disengagements per plate appearance. The two-disengagement limit is reset if a runner advances during the plate appearance. If warranted by special circumstances, umpires may provide extra time beyond the standard timer limits.
• Defensive shift limits: When the pitcher is on the rubber, the defensive team must have a minimum of four players within the outer boundary of the infield, with at least two infielders completely on each side of second base. Infielders may not switch sides. If infielders are not properly positioned when the ball is pitched, the offense can choose either an automatic ball or the result of the play. Outfielders are not affected by this rule, and may even position themselves within the infield.
• Base size: The three bases increased in size from 15-inch squares to 18-inch squares. (Home plate did not change.) This resulted in a 4.5-inch reduction in the distance between adjacent bases, as measured between their nearest edges. There was also a 3-inch reduction in the distance from home plate to the nearest edge of first and third base.

1973: The designated hitter

The two leagues play with basically the same rules, with one notable exception that started with the 1973 season. In the National League, the pitcher, when his turn in the batting order comes, must either bat or be replaced by a pinch hitter. This was also the case in the American League up through the 1972 season. Since 1973, teams in the American League may (and almost always do) designate a different player to bat in the pitcher's spot. This player is known as the "Designated Hitter" or "DH". This player is not allowed to play any positions in the field, and if he is moved or taken from the game, must be replaced in the line-up by the pitcher. In the case of inter-league games, whether in the pre-season, the regular season, or the World Series, the two teams play by the rules of the home team's league.

1969: Height of pitcher's mound

Starting with the 1969 season, the pitcher's mound was lowered from 15 inches to 10 inches above ground level.

Labor relations

From very early on, Major League Baseball and its players have had a fractious relationship. In an effort to gain some momentum in their disagreements with the owners, the players formed a labor union in 1954. This union, known as the Major League Baseball Players Association or, MLBPA, got off to a slow start. Likely due in part to the MLBPA's first Director, Robert Cannon's, friendly relationship with the owners, the owners and the players did not function under a collective bargaining agreement (CBA) until 1968, after the hiring of the MLBPA's first full-time head man, Marvin Miller. This first agreement made some small concessions in favor of the players, including an increase in the minimum salaries. The next deal was agreed on in 1970, with some more gains made by the players.

The first major point of contention between the two sides would be first negotiated in the 1973 CBA. The issue was free agency, or whether or not the players would have the right to go to any team in baseball after the end of a contract, instead of the rights to sign a player staying with the same team, unless that team chose to forego those rights. What started the disagreement was the "reserve clause" that was put into the contract of every player. The debate was whether this clause allowed the teams to renew the player's contract indefinitely, or, if after playing a year without the player's renewal, this contract automatically expired. An arbitrator, Peter Seitz, would rule in favor of the players. This led to the first work-stoppage, with the owners locking the players out until late March of 1976 when a federal judge would uphold Seitz's decision.

Despite restrictions on how often and with whom the players were allowed to negotiate a free-agent contract, the average player's salary skyrocketed, going from $51,501 to $143,756 annually in just 4 years. This led to a new proposal from the owners, the right to be compensated, in the form of a different player, for a player leaving for another team. This was met with severe resistance from the players' union. An agreement was eventually reached between the two sides, but not before 712 games of the 1980 season were canceled. The compensation system that was put in place was confusing for all involved, but especially for the fans, and it was dropped with little ado in the next CBA negotiations in 1985.

Another part of the 1985 discussions centered around salary arbitration. With the arbitration system, if a player and a team cannot agree on a contract prior to that player being eligible for free agency, they may submit to binding arbitration. The owners wanted to reduce the number of arbitration-eligible players by raising the threshold for arbitration from two years to three. They also sought to cap the increase in salary that an arbitrator could award. The players again struck. Two days after the strike, the two sides reached a compromise and a new, five-year CBA was reached.

During the 1985 CBA, the owners were accused by the players of collusion. After having lost some ground in the CBA, the owners decided amongst themselves to not sign one another's free agents. This was a clear violation of the CBA, and after several arbitrations, the owners ultimately paid the player $280 million in compensation.

When negotiations for the new CBA started in 1990, several of the owners drew a hard line. Making demands to win back some of the concessions they had made in previous agreements. The players, in response, made several new demands of their own, including pushing back the arbitration threshold to the 2-year mark it had been prior to 1985. The owners locked the players out, causing the third work stoppage in baseball in 15 years. This stoppage lasted 32 days, after which the owners dropped their demands, and even gave in to some of the players' proposals.

The owners blamed much of what happened during the 1990 CBA on then commissioner Fay Vincent. Several of the owners moved to force Vincent out and steeled themselves for the next negotiations. These negotiations started in 1994, with the owners proposing a salary cap, which, if enforced, would have resulted in a collective 15% pay cut for the players. This move infuriated the players, forcing them to strike on August 12, 1994. Several weeks later, the players proposed a counteroffer, which included revenue sharing, and a small luxury tax, but no salary cap. The owners held their ground, and the rest of the season, including the 1994 playoffs and World Series were canceled. The next season did start on time, but not before a federal judge forced the owners to play under the same rules as the previous agreement until a new one was reached. This new agreement was not reached until 1996. The owners gained significant ground in the new agreement, which included a steep luxury tax for the teams with the highest payrolls and increased revenue sharing.

Before negotiations started for the 2002 CBA, the owners, led by commissioner Bud Selig, put a commission in place to help determine what would be in the best interest of baseball. This commission's recommendations became, in large part, the new agreement reached by both sides. This agreement was reached with no work stoppage. Since that time, the players and the owners have butted heads in the realm of performance-enhancing drugs, and the ways that they are tested for and abusers punished, but each of the several agreements reached regarding this drug policy has been reached with no work stoppages.

League Structure and Playoffs

Each major league baseball team currently plays a 162-game season every year. This has been the case in the American League since 1961 and in the National League since 1962, coinciding with each league's expansion from 8 to 10 teams. Teams play more games against divisional opponents, fewer games against league opponents from other divisions, and the fewest games against teams from the other league. Starting with the 2023 season, the breakdown is as follows.

• 13 games against each of 4 divisional opponents (52 total games)
• 6 or 7 games against each of 10 league opponents from other divisions (64 total games)
• 3 or 4 games against each of 15 opponents from the other league (46 total games)

The subdividing of each league into divisions began in 1969, with the creation of Eastern and Western divisions in each league. This coincided with the expansion of each league from 10 teams to 12 teams. The two leagues have used the same divisional structure and playoff format as each other every year as follows.

• 2022-present
  • Three divisions per league, as in previous years
  • New: six playoff teams (per league)
  • Playoffs still include the regular-season winner of each division.
  • Wild card expands to three teams (per league) -- or shrinks to three teams, compared to the pandemic-shortened 2020 season.
  • The two division winners with the best records among division winners get a first-round playoff bye.
  • The three wild card teams, plus the division winner with the worst record among the three division winners, meet in a best-of-three format playoff series.
  • Wild card round among 4 teams (per league) narrows the playoff field from 6 to 4 teams total (again, per league): The two wild-card-round winners and the two teams with first-round byes.
  • LDS and LCS still follow best-of-five and best-of-seven formats, respectively.
• 2012-2021, EXCEPT for 2020:
  • Three divisions per league, as in previous years
  • New: five playoff teams (per league)
  • Playoffs still include the regular-season winner of each division.
  • Wild card expands to two teams (per league) that meet in a single-game playoff to advance to the LDS.
  • LDS and LCS still follow best-of-five and best-of-seven formats, respectively.
• 2020 only
  • Pandemic-shortened season, with a novel one-time playoff format owing to the short 60-game regular season.
  • Three divisions per league, as in previous years
  • New: eight playoff teams (per league)
  • Playoffs still include the regular-season winner of each division.
  • Wild card expands to five teams (per league) for this season only.
  • All eight playoff teams play in a best-of-three Wild Card round, with no first-round byes.
  • LDS and LCS still follow best-of-five and best-of-seven formats, respectively.
• 1995-2011:
  • Three divisions per league, as in the previous year, but first postseason with three-division format.
  • New: four playoff teams (per league)
  • Playoffs include the regular-season winner of each division.
  • Additionally, one "wild card" team, the non-division-winner with the best record, is in the playoffs.
  • The first round of playoffs, the "American/National League Division Series" (ALDS, NLDS), follows a best-of-five format.
  • LCS is still best-of-seven format.
• 1994 only:
  • New: Three divisions per league (East, Central, and West).
  • No postseason due to players' strike.
• 1985-1993:
  • Two divisions per league, as in previous years
  • Two playoff teams (per league), as in previous years
  • LCS expands to best-of-seven format.
• 1969-1984, EXCEPT for 1981:
  • New: Two divisions per league, East and West (per league)
  • New: Two playoff teams (per league), which are the two division winners.
  • The regular-season winner of each division meets in a best-of-five playoff, the "League Championship Series" (LCS, or ALCS and NLCS), to determine the pennant winner (a.k.a. league champion).
• 1981 only:
  • Owing to a players' strike in midseason, the teams with the best pre-strike and post-strike records in each division met in a best-of-five playoff, the "League Division Series," (LDS), to determine the division winners.
  • Four playoff teams (per league)
  • LDS is best-of-five format.
  • LCS is still best-of-five format.
• Up through 1968:
  • No divisions
  • The regular-season winner of each league is the league champion and is said to have "won the pennant," moving on to the World Series.

Summary table:

Years	Number of divisions (per league)	Number of playoff teams (per league)	LCS format	LDS format	Wild card round format
2022-present	3	6	Best of 7	Best of 5	Best of 3
2012-2021, EXCEPT 2020	3	5	Best of 7	Best of 5	Single game
2020 only*	3	8	Best of 7	Best of 5	Best of 3
1995-2011	3	4	Best of 7	Best of 5
1994 only*	3	No playoffs
1985-1993	2	2	Best of 7
1969-1984, EXCEPT 1981	2	2	Best of 5
1981 only*	2	4	Best of 5	Best of 5
Through 1968	1	1

• In 2020 the playoff format was revised owing to the covid pandemic.
• In 1994 there were no playoffs owing to a players' strike that ended the season early.
• In 1981 the playoff format was revised owing to a midseason players' strike.

All-Star Game

In July of every year, every team has a three-day break in their schedule, called the "All-Star Break". In the middle of this break, there is a special exhibition game called the All-Star game. This game features at least one player from every team in the Major Leagues. They are split up into two teams, one team featuring players from the American League, and the other team having players from the National League. The starting position players (as in, the non-pitchers) are voted on by the fans. The player receiving the most votes from the fans at each position in each league starts in the game, though they will usually only play a few innings. The rest of the team is chosen by, in large part, the manager of their respective teams. The players and the Commissioner's office also have some say in the rest of the roster for this game. The managers from the two teams that were in the World Series the year prior are chosen to lead the All-Star teams.

Since starting in 1933, the All-Star game has been played almost every year. There were two games per year during the four-year stretch from 1959 through 1962, no All-Star games in 1945 (due to World War II) and 2020 (due to the Covid pandemic), and one game per year otherwise. Prior to 2003, it was a meaningless exhibition game, having no bearing on any other part of the season. This changed when, after the 2002 All-Star game was called a tie due to a lack of pitchers on both teams, it was decreed by the Commissioner, Bud Selig, that the winning league in the All-Star game would have home-field advantage (playing 4 of the 7 games in their own stadium) in the World Series that season.

The Minors

Major League Baseball is the highest level of professional baseball in North America. Below it are the minor leagues, ranked AAA, AA and A. The Minors include such leagues as the International League and the Southern League, which typically have teams in smaller cities and towns throughout the U.S. and Canada. Major League teams use the Minors as development leagues for younger players. They also provide an opportunity for older players trying to work their way back into the Majors as well as employment for players who were never able to make it to "The Show," as the big leagues are sometimes called.

Leagues

Throughout the years, both leagues have seen a number of teams come and go. When the National League was formed in 1876, it had eight teams, only four of which are still in existence and in the same city that they started in. When the American League was formed in 1901, it also had eight teams, seven of which are still where they started. Additionally, these are not the only major leagues to have existed. The National Association predated the National League and was active from 1871 to 1875. The American Association was active from 1882 to 1891, and its champion played the National League champion in a 19th-century version of the World Series from 1884 to 1890. For a complete list of major baseball leagues other than the National and American Leagues, see the section "Inactive Major Leagues" at the following reference.

List of current teams in Major League Baseball

• American League
  • East Division
    • Baltimore Orioles
    • Boston Red Sox
    • New York Yankees
    • Tampa Bay Rays
    • Toronto Blue Jays
  • Central Division
    • Chicago White Sox
    • Cleveland Guardians
    • Detroit Tigers
    • Kansas City Royals
    • Minnesota Twins
  • West Division
    • Houston Astros
    • Los Angeles Angels
    • Oakland Athletics
    • Seattle Mariners
    • Texas Rangers

• National League
  • East Division
    • Atlanta Braves
    • Miami Marlins
    • New York Mets
    • Philadelphia Phillies
    • Washington Nationals
  • Central Division
    • Chicago Cubs
    • Cincinnati Reds
    • Milwaukee Brewers
    • Pittsburgh Pirates
    • St. Louis Cardinals
  • West Division
    • Arizona Diamondbacks
    • Colorado Rockies
    • Los Angeles Dodgers
    • San Diego Padres
    • San Francisco Giants