minor league vs small potatoes

minor league

adj
  • Having a quality less than the best possible. 

noun
  • An association of sports teams that plays at a level below the major leagues of a sport. 

small potatoes

noun
  • One or more persons or things of relatively little consequence, importance, or value. 

How often have the words minor league and small potatoes occurred in a corpus of books? (source: Google Ngram Viewer )