Here are the roster limits by league:
Triple-A: International, Pacific Coast - 25 active.
Double-A: Eastern, Southern, Texas - 25 active.
Class A Advanced: California, Carolina, Florida State - 25 active; 35 under control; no more than two players and one player-coach on active list may have six or more years of prior Minor League service.
Class A: Midwest, South Atlantic - 25 active; 35 under control; no more than two players on active list may have five or more years of prior Minor League service.
Class A Short-Season: New York-Penn, Northwest - 35 active. No more than three players on the Active List may have four or more years of prior Minor League service.
Rookie: Appalachian, Pioneer leagues - 35 active. No more than three players on the Active List may have three or more years of prior Minor League service.
Rookie: Arizona, Gulf Coast leagues - 35 active. No player on the Active List may have three or more years of prior Minor League service.
Rookie: Venezuelan Summer, Dominican Summer - 35 active. No player on the Active List may have four or more years of prior Minor League Service. No Draft-eligible player from the U.S. or Canada (not including players from Puerto Rico) may participate in the DSL or VSL.
As per
https://www.milb.com/about/faqs-business