Major League Baseball (MLB) is the highest level of play in North American professional baseball. More specifically, Major League Baseball refers to the organization that operates North American professional baseball's two leagues, the National League and the American League, by means of a joint organizational structure which has existed between them since 1903. Major League Baseball teams play a 162 game season. The American League operates under the Designated Hitter Rule, but the National League does not (inter-league, all-star and World Series game rules are determined by the home team's league rules). In 2000, the American and National Leagues were officially disbanded as separate legal entities with all rights and functions consolidated in the commissioner's office. MLB effectively operates as a single league and as such it constitutes one of the major professional sports leagues of North America.
Major League Baseball is controlled by an agreement that has undergone several incarnations since 1876, then called the NL Constitution, with the most recent revisions being made in 2005. Major League Baseball, under the direction of its Commissioner, Bud Selig, hires and maintains the sport's umpiring crews, and negotiates marketing, labor, and television contracts. As is the case for most North American sports leagues, the 'closed shop' aspect of MLB effectively prevents the yearly promotion and relegation of teams into the Major League by virtue of their performance.
MLB maintains a unique, controlling relationship over the sport, including most aspects of minor league baseball. This is due in large part to a 1922 U.S. Supreme Court ruling in Federal Baseball Club v. National League which held that baseball is not interstate commerce and therefore not subject to federal antitrust law despite baseball's own references to itself as an "industry" rather than a "sport." This ruling has been weakened only slightly in subsequent years.
The production/multimedia wing of MLB is New York-based MLB Advanced Media which oversees MLB.com and all 30 of the individual teams' websites. Its charter states that MLB Advanced Media holds editorial independence from the League itself, but it is indeed under the same ownership group and revenue-sharing plan. MLB Productions is a similarly-structured wing of the league, focusing on video and traditional broadcast media.
Current Major League Clubs:
The Major League regular season runs from the first Monday in April (with one game the Sunday night before) until late September or early October. Players and teams prepare for the season in spring training, in Florida and Arizona, during February and March. Three rounds of playoffs follow the regular season, culminating in the World Series in late October.
The Commissioner of baseball, Bud Selig, has often floated the idea of international expansion and realignment of the major leagues. At the moment, however, the two major leagues are each split into three divisions and structured as listed in the tables above.
In all, there are 30 teams in the two leagues: 16 in the older National League ("NL") and 14 in the American League ("AL"). The leagues do not have the same number of teams because an odd number of teams would force at least one team to be off every day, or play a team from the opposite league. Each has its teams split into three divisions grouped generally by geography. They are (number of teams in each division in parenthesis): NL East (5), NL Central (6), NL West (5), AL East (5), AL Central (5), and AL West (4).
Each team's regular season consists of 162 games, a duration established in 1961 in the American League and 1962 in the National League. From 1904 into the early 1960s, except for 1919, a 154-game schedule was played in both leagues (7 opponents X 22 games apiece). Expansion from 8 to 10 teams in each league in the early 1960s resulted in a revised schedule of 162 games (9 opponents X 18 games apiece, initially) in their expansion years, for the American League in 1961 and the National League in 1962. Although the schedule remains at 162 games to this day, the layout of games played was changed when Divisional play began in 1969, so that teams played more games against opponents within their own division than against the other divisions or (beginning in 1997) the other league.
Unplanned shortened seasons were played in 1918 due to the United States entering World War I, and in 1972, 1981, 1994 and 1995 due to player strikes and lockouts. A 140-game schedule (7 X 20) was played in 1919, due to the influenza outbreak, and the schedule before 1904 varied from year to year.
Games are played predominantly against teams within each league through an unbalanced schedule which heavily favors intra-divisional play. In 1997, Major League Baseball introduced interleague play, which was criticized by the sport's purists but has since proven very lucrative to the franchises.
The interleague games are confined to the mid-summer months. Typically many intra-division games are scheduled toward the end of the season, anticipating the possibility of close divisional races and heightened fan interest.
Each year in June, Major League Baseball conducts a draft for first-year players who have never signed a Major or Minor League contract. The Major League Baseball Draft is among the least followed of the professional sports drafts in the United States, possibly because other professional sports drafts feature players who will immediately start to play for the team they are drafted by that next year, whereas the MLB has an extensive minor league system to help players mature and hone their skills to be able to compete with those in the major leagues.
Post-season:
When the regular season ends after the first Sunday in October (or the last Sunday in September), eight teams enter the post-season playoffs. Six teams are division champions; the remaining two "wild-card" spots are filled by the team in each league that has the best record but is not a division champion (best second-place team).
Three rounds of series of games are played to determine the champion:
1. American League Division Series and National League Division Series, each a best-of-five game series;
2. American League Championship Series and National League Championship Series, each a best-of-seven game series played between the surviving teams from the ALDS and NLDS; and
3. World Series, a best-of-seven game series played between the champions of each league.
The division winners are seeded 1-3 based on record. The wild-card team is the 4 seed, regardless of its record.
The matchup for the first round of the playoffs is usually 1 seed vs. 4 seed and 2 seed vs. 3 seed, unless the wild-card team is from the same division as the 1 seed, in which case the matchup is 1 seed vs. 3 seed and 2 seed vs. 4 seed, as teams from the same division cannot meet in the 1st round.
In the first and second round of the playoffs, the better seeded team has home-field advantage, regardless of record.
In the event of a tie in the standings at the close of the regular season, league rules provide for a one-game playoff (with the home field determined by head-to-head record) to determine which of two teams participate in the Division Series. If three teams are involved in a tie, a two-game playoff may be played.
If two teams are tied, but a tiebreaker would result in both participating in the Division Series anyway (due to one being division champion and the other being wild card), then no playoff is played and seedings are determined by head-to-head record.
The team belonging to the league that won the mid-season All-Star Game receives home-field advantage in the World Series.
