A (short-season)

From BR Bullpen

While most class A leagues play a schedule around 140 games long, some start only after that year's amateur draft, with a season lasting about 75 contests. As of 2006, there are only two such leagues in existence at the Single-A level (there are more at the Rookie level) - the New York-Penn League and Northwest League. The leagues are usually stocked with recently drafted college players, with occasional top high school prospects (usually sent to Rookie leagues instead) or players who have some limited professional experience.