Minor League Baseball prepares players for leagues.
Generally, the parent major league club pays the salaries and benefits of uniformed personnel (players and coaches) and provides bats and balls, while the minor league club pays for in-season travel and other operational expenses
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

