Voting now open in 2021 Best of the Ballparks, MLB Partner Leagues

The four MLB Partner Leagues came about during the offseason reorganization of Minor League Baseball. Three former independent leagues–the American Association, Atlantic League and Frontier League–were offered and accepted MLB Partner League status. The Pioneer League, formerly an affiliate Rookie league, transitioned to an MLB Partner League as well. Several former affiliated teams that did not make the 120-team cut also ended up joining MLB Partner Leagues. They're all represented here. (OK, strictly speaking, not every ballpark here is part of an MLB Partner League: Jimmy John's Field and Volcanoes Stadium host professional baseball and fall under the imprimatur of independent baseball.)