<P> Going into the 2010 season, the longest continuous link between major league and minor league clubs was the link between the Orioles and their Rookie - level Appalachian League affiliate, the Bluefield Orioles . The teams were affiliated for 53 years, from 1958 through 2010 . Baltimore ended the PDC after the 2010 season . At the start of the 2011 season, the longest continuous affiliations were two 45 - year links: between the Philadelphia Phillies and their Double - A Eastern League affiliate, the Reading Fightin Phils; and the one between the Detroit Tigers and their Class A-Advanced Florida State League affiliate, the Lakeland Flying Tigers . Both Reading and Lakeland are owned by their parent Major League clubs . </P> <P> There are several baseball clubs that operate teams at multiple levels of the minor leagues; they are not required to affiliate all of their clubs to the same major league franchise . Bob Rich, Jr., for example, owns the Triple - A Buffalo Bisons and the short - season West Virginia Black Bears, the latter of which had been the Jamestown Jammers before the 2015 season . Even though the teams were located slightly more than 70 miles (110 km) apart before the Jammers' relocation, Rich has never affiliated the two teams with the same parent club . </P> <P> The current minor league classification system divides leagues into one of five classes, those being Triple - A (AAA), Double - A (AA), Class A (Single - A or A), Class A Short Season, and Rookie . Furthermore, Class A is further subdivided into Class A and Class A-Advanced (often called Low - A and High - A, respectively), and Rookie is further subdivided into Rookie Advanced, Complex - based Rookie and international summer baseball . Under the rules governing the affiliated minor leagues (specifically Major League Baseball Rule 51), Class A Short Season is a separate classification from the other leagues bearing the "Class A" name, despite the similarity in name . </P> <P> This classification currently includes two affiliated leagues: the International League and the Pacific Coast League, which feature teams from Eastern and Western United States respectively . For most of the 20th century, it also contained the American Association, based in the Midwest, but that league disbanded, its clubs absorbed by the other two leagues, as part of a reorganization of the Triple - A level in 1997 . The Mexican League is also classified as a Triple - A league, though its clubs do not have PDCs with Major League clubs . </P>

How many divisions are there in minor league baseball