As of the 2022 season, the minor league system is divided into four classes: Triple-A (AAA), Double-A (AA), High-A (A+), and Single-A (A). Major League Baseball franchises may also maintain one or two complex-based … See more

Major league clubs may only use players who are on the team's major league active roster in games; players on the active roster are selected from a 40-man major league reserve list … See more

Umpires at the minor league level are overseen by Minor League Baseball Umpire Development (MiLBUD), which is responsible for the training, evaluation, and recommendation for promotion and retention or release of the umpires.
The umpires are … See more

Minor League Baseball was governed through a centralized office until the restructuring of the minor leagues in 2021, with Major League … See more

The earliest professional baseball league, the National Association of Professional Base Ball Players of 1871 to 1875, commonly referred to as the National Association, … See more

19th century
The earliest classifications used in the minor leagues began circa 1890, for teams that were party to the National Agreement of 1883. The different … See more

Teams in the affiliated minor leagues are generally independently owned and operated, and are directly affiliated with one major league … See more