The following was yoinked from this guy here:
SOURCE
1958 - In a bid to get New York City a non-Yankees baseball team, attorney William Shea files a challenge to the MLB's antitrust exemption. The MLB, rather than expand to neuter the challenge, says, "I'd like to see you try."
1960 - The new Continental League begins play with eight teams: the Atlanta Eagles, Buffalo Bisons, Dallas Rangers, Denver Bears, Houston Colts, Minnesota Twins, New York Metropolitans, and Toronto Huskies
1962 - The Shea Case is decided in the CL's favor and the MLB reluctantly allows the CL to become the third league in the MLB.
1964 - The CL teams join the AL and NL in the MLB. Following the merger, the World Series is changed to a round-robin format at a neutral site. Each of the three league champions will face each other twice, and the top two teams will play a three-game series for the championship, The All-Star Game is also split into three All-Star Series, with AL-CL in late May, CL-NL in mid-June, and AL-NL in early July.
1966 - Nervous about not having a New York team, the NL decides to shore up their control of the West Coast by moving the Milwaukee Braves to Seattle. Also, to compete with the AL and NL, the CL announces they will have a new position: the designated hitter. The CL also announces an intention to expand to 10 teams by 1970.
1967 - It has become an open secret that Athletics owner Charlie Finley wants to leave Kansas City. A group of Milwaukee investors, still sore from losing the Braves, purchase… *drumroll* …the Chicago White Sox? While strange, the White Sox move frees up Chicago for the AL, which spurs Finley to move the Athletics. The Milwaukee White Sox and Chicago A's begin play next season.
1970 - Making good on its expansion announcement, the CL adds the Kansas City Royals and, to give the Braves a rival, the Vancouver Grizzlies.
1971 - Not wanting to be left behind in expansion, the NL adds the San Diego Padres and Montreal Expos.
1972 - Stuck as the last to the expansion party, the AL adds the Miami Marlins and New Orleans Blues. Each league now has 10 teams, and they divide them into two divisions of five teams. The All-Star Series is changed back to an All-Star Game of East Divisions vs. West Divisions.
1973 - The AL gains a West Coast foothold when the Washington Senators move to become the Oakland Mariners and, after one disastrous season, the New Orleans Blues move to become the Anaheim Angels. Also, the AL adopts the DH rule.
1980 - During a decade fraught with economic troubles, two-to-three-hour time zone differentials, and energy crises, travel costs soar. The Pittsburgh Pirates, growing dissatisfied with their lease on Three Rivers Stadium, decided to move to New Orleans's new stadium where the NFL's Jazzmen play.
1983 - To decrease travel costs, the MLB institutes interleague play.
1985 - Due a downturn in the Canadian dollar, the Vancouver Grizzlies move to become the Washington Rivermen.
1992 - Hurricane Andrew forces the Marlins to finish their season in Tampa.
1994 - A World Series-cancelling labor dispute forces the MLB to announce expansion to curtail the rise of another rival league. Two new teams and a fourth league will begin play in 1997.
1997 - The International League begins play, as do the Pittsburgh Pythons and Tampa Rays. The AAA International League is renamed the American Association, and AAA realignment takes place. To balance out the AL and CL, the IL will not use the DH rule. The World Series is now a five-game series between the division winners, followed by a seven-game series in a 1v4 and 2v3 format seeded based on the league champions' regular season records, followed by a seven-game series between those winners. The All-Star Game is changed once again to a two-day All-Star Extravaganza, consisting of six three-inning games, with the AL-CL, IL-NL, and CL-IL games on Tuesday, and the AL-NL, AL-IL, and CL-NL games on Wednesday. Additionally, the pitch clock and all the other game-speeding stuff that happened in OTL 2023 is instituted.
2002 - The CL adds the Arizona Diamondbacks and Carolina Infantry (based out of Charlotte).
2004 - An ownership crisis causes the Montreal Expos move to become the San Juan Senadores.
2005 - Hurricane Katrina forces the Pirates to finish their season in San Antonio.
2007 - The AL adds the Kentucky Mustangs and San Antonio Caballeros.
2012 - The NL adds the Las Vegas Aces and Memphis Pharaohs.
2017 - Thanks to a rebounding Canadian dollar, the IL finally lives up to its name and adds the Montreal Owls and Vancouver Mounties. Also, Hurricane Maria forces the San Juan Senadores to finish their season in Oklahoma City.
2020 - Following the death of George Floyd, the Cleveland Indians and Seattle Braves are renamed the Spiders and Heroes, respectively.
2022 - The DH rule becomes universal. Also, following the retrocession of the District of Columbia to Maryland, the Washington Rivermen rename themselves the DC Rivermen, with the DC standing for "Douglass County".
So, here's how baseball stands today:
Major League Baseball
American League
East Division: Baltimore Orioles, Boston Red Sox, Cleveland Spiders, Detroit Tigers, New York Yankees
West Division: Anaheim Angels, Chicago Athletics, Kentucky Mustangs, Oakland Mariners, San Antonio Caballeros
Continental League
East Division: Atlanta Eagles, Buffalo Bisons, Carolina Infantry, DC Rivermen, Toronto Huskies
West Division: Arizona Diamondbacks, Denver Bears, Dallas Rangers, Houston Colts, Kansas City Royals
International League
East Division: Miami Marlins, Montreal Owls, New York Metropolitans, Pittsburgh Pythons, San Juan Senadores
West Division: Chicago Cubs, Milwaukee White Sox, Minnesota Twins, St. Louis Cardinals, Vancouver Mounties
National League
East Division: Cincinnati Reds, Memphis Pharaohs, New Orleans Pirates, Philadelphia Phillies, Tampa Rays
West Division: Las Vegas Aces, Los Angeles Dodgers, San Diego Padres, San Francisco Towers, Seattle Heroes