Editing Major League Baseball (section)

==League organization==
In 1920, the weak National Commission, created to manage relationships between the two leagues, was replaced with the much more powerful commissioner of baseball, who had the power to make decisions for all of professional baseball unilaterally.<ref name="MLBCommissioner" /> From 1901 to 1960, the [[American League]] and [[National League (baseball)|National League]] fielded eight teams apiece.

In the 1960s, MLB expansion added eight teams, including the first non-U.S. team (the [[Montreal Expos]]). Two teams (the [[Seattle Mariners]] and the [[Toronto Blue Jays]]) were also added in the 1970s. From 1969 through 1993, each league consisted of an East and West Division. In 1993, the National League expanded with two teams, the [[Florida Marlins]] and the [[Colorado Rockies]], to even up the number of teams in both leagues. A third division, the Central Division, was formed in each league in 1994. Until 1996, the two leagues met on the field only during the [[World Series]] and the [[Major League Baseball All-Star Game|All-Star Game]]. Regular-season [[interleague play]] was introduced in 1997.<ref name=Interleague>{{cite news|title=Interleague play ho-hum to some|url=https://news.google.com/newspapers?id=HjMfAAAAIBAJ&pg=2778,783864|access-date=November 24, 2013|newspaper=[[Spartanburg Herald-Journal]]|date=June 4, 2000|archive-date=April 19, 2021|archive-url=https://web.archive.org/web/20210419073021/https://news.google.com/newspapers?id=HjMfAAAAIBAJ&pg=2778%2C783864|url-status=live}}</ref>

In March 1995, two new franchises, the [[Arizona Diamondbacks]] and Tampa Bay Devil Rays (now known as the [[Tampa Bay Rays]]), were awarded by MLB, which began play in 1998. This addition brought the total number of franchises to 30. In early 1997, MLB decided to assign one new team to each league: Tampa Bay joined the AL and Arizona joined the NL. The original plan was to have an odd number of teams in each league (15 per league, with five in each division), but in order for every team to be able to play daily, this would have required inter-league play to be scheduled throughout the entire season. However, it was unclear at the time if the inter-league play would continue after the 1998 season, as it had to be approved by the players' union. For this and other reasons, it was decided that both leagues should continue to have an even number of teams, and therefore, one existing club would have to switch leagues. The [[Milwaukee Brewers#1994–98: Realignment / "We're taking this thing National"|Milwaukee Brewers]] agreed in November 1997 to move from the AL to the NL, thereby making the AL a 14-team league and the NL a 16-team league. At the same time, the [[Detroit Tigers]] agreed to move from the AL East to the AL Central (to replace Milwaukee), with the expansion Tampa Bay Devil Rays joining the AL East.<ref>{{cite news|url=http://www.cincypost.com/sports/1997/brew110697.html|title=Brewers switch leagues, join Reds in NL Central|work=[[The Kentucky Post]] ([[Associated Press]])|date=November 6, 1997|archive-url=https://web.archive.org/web/20050505095313/http://www.cincypost.com/sports/1997/brew110697.html |archive-date= May 5, 2005 |url-status=dead}}</ref> Later, when the [[Houston Astros]] changed ownership prior to the 2013 season, the team moved from the NL Central to the AL West,<ref>{{cite web|last=Bloom|first=Barry M.|title=Sale of Astros to Jim Crane, move to American League in 2013 approved|url=http://m.astros.mlb.com/news/article/25992120|publisher=[[MLB Advanced Media]]|website=Astros.com|date=November 17, 2011|access-date=August 9, 2015|archive-url=https://web.archive.org/web/20150912113823/http://m.astros.mlb.com/news/article/25992120|archive-date=September 12, 2015|url-status=dead}}</ref><ref name="ESPN-AstrosSale2011" /> resulting in both leagues having three divisions of five teams each and allowing all teams to have a more balanced schedule.<ref name="ESPN-AstrosSale2011" /> Inter-league play is now held throughout the season.<ref name="ESPN-AstrosSale2011">MLB required the Astros to accept this move as a condition of approving their sale to [[Jim Crane]].{{cite news|agency=Associated Press|title=Astros' sale finalized; 2 more for playoffs|work=ESPN|date=November 17, 2011|url=https://www.espn.com/mlb/story/_/id/7246443/houston-astros-sale-approved-mlb|access-date=November 17, 2011|archive-date=April 10, 2012|archive-url=https://web.archive.org/web/20120410031253/http://espn.go.com/mlb/story/_/id/7246443/houston-astros-sale-approved-mlb|url-status=live}}</ref>

In 2000, the AL and NL were dissolved as legal entities, and MLB became a single, overall league ''de jure'', similar to the [[National Football League]] (NFL), [[National Basketball Association]] (NBA) and [[National Hockey League]] (NHL)—albeit with two components called "leagues" instead of "conferences". The same [[Baseball rules|rules]] and [[regulation of sport|regulations]] are used in both leagues, with one former exception: the AL operated under the [[designated hitter]] (DH) rule, while the NL did not.<ref name="DHRule">{{cite web|title=Designated Hitter Rule|url=https://www.mlb.com/glossary/rules/designated-hitter-rule|publisher=[[MLB Advanced Media]]|website=[[MLB.com]]|access-date=February 22, 2018|archive-date=February 22, 2018|archive-url=https://web.archive.org/web/20180222104930/http://m.mlb.com/glossary/rules/designated-hitter-rule|url-status=live}}</ref><ref name=Anderson>{{cite news|last=Adamson|first=Scott|title=Nothing more irritating than playing by one set of rules in one park and a different set in another|url=http://www.independentmail.com/news/2011/jul/01/nothing-more-irritating-playing-one-set-rules-one/|newspaper=[[The Anderson Independent-Mail]]|access-date=November 24, 2013|url-status=dead|archive-url=https://web.archive.org/web/20131203014147/http://www.independentmail.com/news/2011/jul/01/nothing-more-irritating-playing-one-set-rules-one/|archive-date=December 3, 2013}}</ref>

In 2020, the NL used the designated hitter (DH) rule for the first time.<ref>{{cite news|last=Feinsand|first=Mark|title=Play Ball: MLB announces 2020 regular season|url=https://www.mlb.com/news/mlb-announces-2020-regular-season|publisher=MLB Advanced Media|website=MLB.com|date=July 6, 2020|access-date=September 9, 2020|archive-date=July 23, 2020|archive-url=https://web.archive.org/web/20200723055403/https://www.mlb.com/news/mlb-announces-2020-regular-season|url-status=live}}</ref> As part of the settlement of the [[2021–22 Major League Baseball lockout]], this change was made permanent thus making the rules in the two leagues identical.<ref name="DHRule" /><ref>{{cite press release|title=New rules for '22 to affect 2-way players, extra innings|url=https://www.mlb.com/news/mlb-rule-changes-for-2022|publisher=[[MLB Advanced Media]]|website=[[MLB.com]]|date=March 31, 2022|access-date=May 5, 2022}}</ref>