Minor League Baseball (MiLB)

What is Minor League Baseball?

Minor League Baseball is the affiliated player-development system of Major League Baseball: 120 full-season clubs in eleven leagues across the United States and Canada, each the farm club of one of the 30 MLB franchises, plus rookie-level complex leagues in Arizona, Florida and the Dominican Republic. It was founded in 1901 as the National Association of Professional Baseball Leagues and has been run directly by MLB since February 2021, when all 120 clubs accepted Professional Development League licences.^[1] [2]

How does it work?

The four levels are Triple-A (International League, Pacific Coast League), Double-A (Eastern, Southern, Texas), High-A (Midwest, Northwest, South Atlantic) and Single-A (California, Carolina, Florida State). Every MLB club supplies exactly one affiliate at each level, and the system is closed: players are assigned by their MLB organisation, which signed them through the draft or as amateur or international free agents — there are no open tryouts. Each league runs its own playoffs — in 2026 from 8 September at Single-A and High-A, 15 September at Double-A and 22 September at Triple-A — and the International and Pacific Coast League champions meet in the single-game Triple-A National Championship, played on 26 September 2026 at Las Vegas Ballpark for the fifth straight year.^{[1] [3] [4]}

How does a player move up?

Promotion is an assignment by the parent club, level by level, under MLB’s own rules; the 2021 restructuring raised minor-league salaries by 38 to 72 percent and put every club in the system on a licence from MLB. Professional leagues outside the licensed system — the Atlantic League, American Association, Frontier League and Pioneer League — are designated MLB Partner Leagues, collaborating with MLB without being affiliates, and the Mexican League, a Triple-A member from 1967 to 2020, left the system in the 2021 restructuring.^{[2] [8] [9]}

Since when does it exist?

The National Association was formed in 1901; MLB’s takeover of 12 February 2021 replaced it with the Professional Development League system and cut the affiliated map to 120 clubs. A unified Triple-A champion has been decided by the National Championship Game since 2006 — 18 games to 2025, the Pacific Coast League winning ten of them — with a three-year Triple-A World Series from 1998 to 2000 the only earlier precedent. Jacksonville’s 2025 title came on an 8–7 walk-off over Las Vegas.^{[1] [3] [5] [6]}

Triple-A National Championship Game winners; no game was played in 2020 or 2021.

Why does it matter?

For a petition, Minor League Baseball is the paradigm of a minor league affiliated with a major league: its clubs exist under licence from MLB, its players are under contract to MLB organisations, and its Single-A, Double-A and Triple-A affiliates are named alongside the major leagues in Canada’s own work-permit guidance.^{[1] [2] [7]}