Minor League Baseball provides player development opportunities.
 Minor league players not on the 40-man reserve list are under contract to their respective parent Major League Baseball clubs
Minor league umpires have been unionized since 1999 to 2023, when they formed the Association of Minor League Umpires (AMLU), which has been a guild within the Office and Professional Employees International Union (OPEIU) since 2010 to 2023

