A classification of minor league professional baseball that is one level below Major League baseball. It is composed of two leagues: the International League and the Pacific Coast League.
AAA baseball, or “Triple-A” as its most commonly spelled out, is one of several levels of minor league professional baseball organized into a hierarchical structure. Like most minor league teams, Triple-A teams are affiliated with Major League teams, although most are independently owned and operated.
For many Major League baseball players, Triple-A baseball leagues were their final step up to the highest level. Players at the Triple-A level are the closest in skill level to those in the majors, and often play harder and smarter in an effort to prove their worth in the event of a call-up.
During the regular season, Major League baseball teams are limited to a 25-man roster, but the overall 40-man roster still exists. The remaining 15 players, who are often called-up through the year for various reasons, play in AAA until the roster expands September 1.
Major League players often train with AAA teams when they are in the process of returning from the disabled list (DL). This process will usually take anywhere from one to two weeks, and these players do not typically play the entire length of a game when they participate.
The Triple-A baseball classification was created in 1946, when it supplanted AA (Double-A) baseball as the highest level of the minor leagues.