drop back vs flush out

drop back

verb
  • Used other than figuratively or idiomatically: see drop, back. 

  • Of a quarterback or other player in the backfield, to take a number of steps back from the line of scrimmage immediately after the snap or hike of the ball, to avoid defenders. 

  • To move to a lower (or slower) position in a race or competition; to slow down so as to meet up with someone behind oneself 

noun
  • The act by a player in the backfield of dropping back from the line of scrimmage after the hike of the ball. 

flush out

verb
  • Used other than figuratively or idiomatically: see flush, out. 

  • To drive out or expose something or someone, as a game bird or other game animal from cover. 

  • To flesh out. 

How often have the words drop back and flush out occurred in a corpus of books? (source: Google Ngram Viewer )