MiLB

MiLB consists of several levels of play. MLB prospects play at each level, typically beginning at the lowest level and earning promotion to higher levels. There are, however, no strict requirements for advancement; prospects may skip levels and some may rarely skip the Minor Leagues altogether. MiLB's levels have been restructured several times, with teams both added and contracted. Most recently, the league eliminated the Short-Season A and Rookie Advanced levels of MiLB in 2021. The five domestic levels of MiLB today are, from lowest to highest, Rookie League, Single-A, High-A, AA (or Double-A) and AAA (or Triple-A). MiLB has also included several foreign leagues throughout its existence, with the only active affiliate being the Dominican Summer League.