minor leaguer vs ballplayer

minor leaguer and ballplayer both are nouns.

Word	Noun	Adjective	Verb	Adverb
minor leaguer	Yes	No	No	No
ballplayer	Yes	No	No	No

As nouns, ballplayer is a hypernym of minor leaguer; that is, ballplayer is a word with a broader meaning than minor leaguer:

Other hypernyms of minor leaguer include baseball player.

minor leaguer (noun)	ballplayer (noun)
a player on a minor-league baseball team	an athlete who plays baseball