minors vs minor league

minors and minor league both are nouns.

Word	Noun	Adjective	Verb	Adverb
minors	Yes	No	No	No
minor league	Yes	No	No	No

As nouns, minors and minor league are synonyms defined as:

minors and minor league: a league of teams that do not belong to a major league (especially baseball)

Other synonyms of minors include bush league.

minors (noun)	minor league (noun)
a league of teams that do not belong to a major league (especially baseball)	a league of teams that do not belong to a major league (especially baseball)