Golden Baseball League Winter League has just completed its third season. In the first three years, over 130 Arizona Winter League players have been signed to professional contracts. Two of those players, Scott Richmond and Sergio Romo, are now pitching in the major leagues. The 2009 Arizona Winter League began play on January 31, 2009 and has expanded to 8 teams and almost 200 players. On April 3, 2009, the Golden Baseball League announced its second instructional league known as the Arizona Summer League, which is patterned after the AWL. This league consists of three teams, the Canada Miners, El Centro Imperials and
Baseball in the United States when St. Louis Cardinals' general manager Branch Rickey formalized the system, and teams in small towns were "growing players down on the farm like corn." As of 2018, the Minor League Baseball hierarchy is separated into the classes of AAA, AA, High-A, A, Short-Season A, Rookie-Advanced and Rookie. Most major league teams have teams in at least six of these seven levels. Major League Baseball and Minor League Baseball teams may enter into a PDC for a two- or four-year term. At the expiration of a PDC term, teams may renew their affiliation, or sign new PDCs with different clubs,