manager vs third string

manager

noun
  • An administrator, for a singer or group. 

  • A person whose job is to manage something, such as a business, a restaurant, or a sports team. 

  • A window or application whose purpose is to give the user the control over some aspect of the system. 

  • The head coach. 

third string

adj
  • Of a decidedly lower quality or condition. 

noun
  • A unit of players that plays behind the first and second strings; a junior varsity team. 

How often have the words manager and third string occurred in a corpus of books? (source: Google Ngram Viewer )