[Le Grande Orange]

Originally Posted by blasek0

From MILB.com, they use the classifications of AAA, AA, A Adv, A, Short Season A, Rookie. AZL/GCL/DSL/VSL/Pioneer/Frontier are all considered a rookie league affiliate with no further breakdowns in classification, as far as the official rules go.

It's not quite that clear since the 2008 edition of the Major League Rules do specify a split of Rookie:

Originally Posted by Major League Rule 51(a)

... Leagues in the Rookie classification also shall be given the further subclassification of Rookie or Rookie-Advanced.

The 2008 and 2009 editions of the Baseball America Directory also shows the split into Rookie Advanced and Rookie, and each had different service time limitations.

Then again, in an article in Jan. of 2008 mentioning some rule changes, there was this tidbit about changes in the minors:

... In Thursday's other rule change, Rule 51 concerning limits on Minor League service time eliminated the distinction between the levels Rookie, where the limit had been two years, and Rookie Advanced, where players could be kept for three years. Henceforth, the three-year limit will apply to both.

So it seems there is some disagreement about just how official the split of Rookie and Rookie Advanced really is.

The main thing that separates them in my mind is that the Rookie, i.e. Arizona and Gulf Coast Leagues do not represent actual towns/cities as the games are played at the spring training complexes of the parent clubs, admission is not charged, and attendance is not tracked. In contrast, the Rookie Advanced leagues, Appalachian and Pioneer, have clubs which play representing specific towns/cities, with their own dedicated parks, and tickets are sold and attendance tracked. In other words, they are 'real' minor leagues (i.e. moneymaking enterprises) whereas the AZL and GCL (along with the foreign DSL and VSL) are more akin to instructional leagues, wholly owned and operated by the parent major league clubs.