ballplayer vs participant

ballplayer and participant both are nouns.

Word	Noun	Adjective	Verb	Adverb
ballplayer	Yes	No	No	No
participant	Yes	No	No	No

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

Other hypernyms of ballplayer include athlete, jock, player.

ballplayer (noun)	participant (noun)
an athlete who plays baseball	someone who takes part in an activity
	a person who participates in or is skilled at some game