Below the High-A level is Single-A, also known as "Single A" or "Class A". Beginning in 2021, this classification has three leagues: Carolina League, Florida State League, and California League, which succeed the Low-A East, Low-A Southeast, and Low-A West, respectively, the latter two having been High-A leagues.
These leagues are a mix of players moving up from Rookie leagues, as well as the occasional experienced first-year player. Most of the teams in Low-A Southeast are owned by major league parent clubs and use their spring training complexes.