After more than a year of speculation about what would happen to Minor League Baseball (MiLB) and its 160 ballclubs affiliated with Major League Baseball (MLB) teams, the clock struck Midnight for dozens of teams during a flood of announcements issued Dec 9, 2020.
That’s the day 25 MLB teams formally announced their 2021 season player development affiliate “invitations.”
As expected, MLB clubs which typically carried five or six teams from Low A to Triple A, all pared down to just four affiliates, with one team at each level: Triple A, Double A, High A and Low A.
Cutting down to 120 teams — plus adding two formerly independent teams (St. Paul Saints, Sugar Land Skeeters) — has resulted in 41 teams losing MLB affiliations.
Three leagues were hit hardest with all their teams affiliations going away: the Appalachian League (10 teams in 2019), New York-Penn League (14) and Pioneer League (8).
The Appy and Pioneer have new life as summer collegiate baseball and “MLB partner league” circuits, respectively. Half of the NYPL’s 14 teams will continue on by moving to either the new Mid-Atlantic League or new college showcase MLB Draft League, however, the NYPL as a league appears to be a goner.
In addition, 10 of 12 Midwest League teams and six of eight Northwest League clubs moved up in classification from Low A to High A, with 11 teams moving down to Low A from several different leagues.
2021 Player Development Structure
| MLB Team |
AAA | AA | High A | Low A | Dropped, No New Affiliation |
| Arizona Diamondbacks (link) | Reno Aces | Amarillo Sod Poodles | Hillsboro Hops | Visalia Rawhide | Jackson Generals (SL>>TBA); Kane Co. Cougars (MWL>>TBA); Missoula PaddleHeads (Pioneer) |
| Atlanta Braves (link) | Gwinnett Stripers | Mississippi Braves | Rome Braves | Augusta GreenJackets | Danville (Appy); Florida Fire Frogs (FSL>>Defunct) |
| Baltimore Orioles (link) | Norfolk Tides | Bowie Baysox | Aberdeen Ironbirds | Delmarva Shorebirds | Frederick Keys (NYPL>>MLBD) |
| Boston Red Sox (link) | Worcester* Red Sox | Portland Sea Dogs | Greenville Drive | Salem Red Sox | Lowell Spinners (NYPL>>TBA) |
| Chicago Cubs (link) | Iowa Cubs | Tennessee Smokies | South Bend Cubs | Myrtle Beach Pelicans | |
| Chicago White Sox (link) | Charlotte Knights | Birmingham Barons | Winston-Salem Dash | Kannapolis Cannon Ballers | Great Falls Voyagers (Pioneer) |
| Cincinnati Reds (link) | Louisville Bats | Chatanooga Lookouts | Dayton Dragons | Daytona Tortugas | Billings Mustangs (Pioneer); Greeneville (Appy) |
| Cleveland Indians (link) | Columbus Clippers | Akron RubberDucks | Lake County Captains | Lynchburg Hillcats | Mahoning Valley Scrappers (NYPL>>MLBD) |
| Colorado Rockies (link) | Albuqurque Isotopes | Hartford Yard Goats | Spokane Indians | Fresno Grizzlies | Boise Hawks (Northwest); Grand Junction Rockies (Pioneer); Lancaster JetHawks (Calif.>>TBA) |
| Detroit Tigers (link) | Toledo Mud Hens | Erie SeaWolves | West Michigan Whitecaps | Lakeland Flying Tigers | Norwich Sea Unicorns (NYPL>>TBA) |
| Houston Astros (link) | Sugar Land Skeeters [i] | Corpus Christi Hooks | Asheville Tourists | Fayetteville Woodpeckers | Tri City Valley Cats (NYPL>>TBA) |
| Kansas City Royals (link) | Omaha Storm Chasers | Northwest Arkansas Naturals | Quad Cities River Bandits | Columbia Fireflies | Burlington, N.C. (Appy); Idaho Falls Chukars (Pioneer); Lexington Legends (SAL>>TBA) |
| Los Angeles Angels (link) | Salt Lake Bees | Rocket City Trash Pandas | Tri-City Dust Devils | Inland Empire 66ers | Burlington Bees (MWL>>TBA); Orem Owlz (Pioneer) |
| Los Angeles Dodgers (link) | Oklahoma City Dodgers | Tulsa Drillers | Great Lakes Loons | Rancho Cucamonga Quakes | Ogden Raptors (Pioneer) |
| Miami Marlins (link) | Jacksonville Jumbo Shrimp | Pensacola Blue Wahoos | Beloit Snappers | Jupiter Hammerheads | Batavia Muckdogs (NYPL>>TBA); Clinton Lumberkings (MWL>>TBA) |
| Milwaukee Brewers (link) | Nashville Sounds | Biloxi Shuckers | Wisconsin Timber Rattlers | Carolina Mudcats | Rocky Mountain Vibes (Pioneer) |
| Minnesota Twins (link) | St. Paul Saints [i] | Wichita Wind Surge | Cedar Rapids Kernels | Fort Meyers Mighty Mussels | Elizabethon (Appy) |
| New York Mets (link) | Syracuse Mets | Binghamton Rumble Ponies | Brooklyn Cyclones | St. Lucie Mets | Kingsport (Appy) |
| New York Yankees (link) | Scranton RailRiders | Somerset Patriots | Hudson Valley Renegades | Tampa Tarpons | Pulaski (Appy); Staten Island Yankees (NYPL>>Defunct); Trenton Thunder (NYPL>>MLBD) |
| Oakland Athletics (link) | Las Vegas Aviators | Midland RockHounds | Lansing Lugnuts | Stockton Ports | Vermont Lake Monsters (NYPL>>TBA) |
| Philadelphia Phillies (link) | Lehigh Valley IronPigs | Reading Fightin Phils | Jersey Shore BlueClaws | Clearwater Threshers | Williamsport Crosscutters (NYPL>>MLBD) |
| Pittsburgh Pirates (link) | Indianapolis Indians | Altoona Curve | Greensboro Grasshoppers | Bradenton Marauders | Bristol (Appy); West Virginia Black Bears (NYPL>>MLBD) |
| San Diego Padres (link) | El Paso Chihuahuas | San Antonio Missions | Fort Wayne TinCaps | Lake Elsinore Storm | |
| San Francisco Giants | Sacramento River Cats | Richmond Flying Squirrels | Eugene Emeralds | San Jose Giants | |
| Seattle Mariners (link) | Tacoma Rainiers | Arkansas Travelers | Everett AquaSox | Modesto Nuts | West Virginia Power (SAL>>TBA) |
| St. Louis Cardinals | Memphis Redbirds | Springfield Cardinals | Peoria Chiefs | Palm Beach Cardinals | Johnson City (Appy); State College Spikes (NYPL>>MLBD) |
| Tampa Bay Rays (link) | Durham Bulls | Montgomery Biscuits | Bowling Green Hot Rods | Charleston Riverdogs | Princeton (Appy) |
| Texas Rangers (link) | Round Rock Express | Frisco RoughRiders | Hickory Crawdads | Down East Wood Ducks | |
| Toronto Blue Jays (link) | Buffalo Bisons | New Hampshire Fisher Cats | Vancouver Canadiens | Dunedin Blue Jays | Bluefield (Appy) |
| Washington Nationals (link) | Rochester Red Wings | Harrisburg Senators | Wilmington Blue Rocks | Fredricksburg Nationals | Auburn Doubledays (NYPL>>TBA); Hagerstown Suns (SAL>>TBA) |
i = previously independent; affiliates owned by parent club are italicized; Blue denotes new affiliation for 2021; Green denotes team moved up classification; Red denotes team dropped down in classification
Outside looking in
Teams that were members of MiLB in 2019/20, now left without either an MLB affiliation or partner league for 2021 (listed by their 2020 league):
- California League (1) — Lancaster JetHawks
- Florida State League (2) — Charlotte Stone Crabs & Florida Fire Frogs both are now defunct
- Midwest League (3) — Burlington Bees, Kane County Cougars & Clinton LumberKings
- South Atlantic League (3) — Hagerstown Suns, Lexington Legends & West Virginia Power
- Southern League (1) — Jackson Generals
- New York-Penn League (7) — Staten Island Yankees folded, while Auburn Doubledays, Batavia Muckdogs, Lowell Spinners, Norwich Sea Unicorns, Tri-City Valley Cats and Vermont Lake Monsters are TBD