Webster's Revised Unabridged Dictionary · 1913

minor league

minor league , noun

Certain minor league sports teams are often owned by those owning a major league club, and the minor league clubs are used to provide practise and opportunity for evaluation for candidates who wish to play in the major leagues.

Sport) A league of professional sports teams less proficient than a major leagues. Players in the minor leagues generally are paid less than those in the major leagues, and their games attract less atention.

minor-league , adjective

Of or pertaining to a minor league.
2.
Of mediocre talent or poor accomplishment; unimportant; -- of people; as, a minor-league physicist.