Minor League Baseball Glossary
Plain-English definitions for terms used across the site and across minor league baseball generally. Playing the Grid or Trivia and hit an unfamiliar word? It's probably here.
- Affiliate
- A minor league club with a formal player-development agreement with one specific MLB organization. Every full-season minor league team is affiliated with exactly one MLB club at a time; "the Triple-A affiliate of the Dodgers" means the top minor league team in the Dodgers' farm system.
- Call-up
- When a player is moved from a minor league roster to the MLB roster, usually because of an injury, a roster expansion, or the organization deciding the player is ready. The players one call-up away from the majors are exactly the players who make up a Triple-A roster.
- Complex league / Rookie ball
- The lowest levels of organized minor league baseball, played mostly at team training complexes rather than in front of paying crowds. Not covered by this site, every game here uses full-season affiliates (Triple-A through Single-A).
- Draft round
- MLB's amateur draft is split into rounds; a player's draft round (1st round, 5th round, etc.) is often used as shorthand for how highly a team valued their potential when signing them.
- Farm system
- An MLB organization's full network of minor league affiliates, one team per level, used to develop young and recovering players before they reach the majors. "The Guardians' farm system" refers to all of Cleveland's minor league clubs together.
- Level
- Minor league baseball is organized into tiers of competition, from the majors on down: Triple-A, Double-A, High-A, and Single-A (the four full-season levels), followed by short-season and rookie-level complex leagues. Triple-A is the highest level and the closest to the majors.
- MiLB
- Shorthand for Minor League Baseball, the collective term for every level below MLB.
- Minor league free agent
- A player who is not on any MLB organization's 40-man roster and is free to sign a minor league contract with any team. Common for veteran players filling out Triple-A rosters late in their careers.
- MLB debut
- A player's first-ever appearance in a major league game. Reaching an MLB debut, even a single game, is the milestone every minor leaguer is ultimately playing toward, and it's a criterion used directly in the Daily Grid.
- Optioned / Option year
- When a player on an MLB organization's 40-man roster is sent down to the minors, they're said to be "optioned." Each player has a limited number of option years available before roster rules require different handling, which is part of why some MLB-caliber players still appear on Triple-A rosters.
- Parent org
- The MLB organization that a given minor league team is affiliated with: same concept as "affiliate," just described from the minor league team's point of view instead of the MLB club's.
- Prospect
- A minor league player, usually young and not yet established in the majors, whose future MLB performance is considered promising based on age, tools, and minor league track record.
- Rehab assignment
- A short minor league stint by an MLB player recovering from injury, used to get game reps before returning to the majors. It's one reason a Triple-A roster can include a genuinely well-known MLB name for a game or two.
- Roster (40-man)
- The 40-man roster is the full set of players an MLB organization controls and could call up to the majors at any time, larger than the 26-man active MLB roster. Most, but not all, Triple-A players are on their organization's 40-man roster.
- Triple-A
- The highest level of minor league baseball, one step below the majors. Every Daily Grid, Trivia, and Higher/Lower question on this site draws from real Triple-A player and stat data; Guess the Nickname is the one game that also reaches into the lower levels.
- Waivers / DFA
- When an MLB organization removes a player from its 40-man roster, it must first "designate them for assignment" (DFA) and pass them through waivers, where any other team can claim them. A player who clears waivers unclaimed can be outrighted to the minors instead.
Want to know how the games themselves are scored? See How It Works.