the ball is in someone’s court

the ball is in (one's) court

One has the responsibility for further action, especially after someone else previously held responsibility. The phrase originated in tennis. Well, they invited you, so the ball is in your court now. Do you want to go out with them or not?
See also: ball, court
Farlex Dictionary of Idioms.

the ball is in someone’s court

phr. to be someone else’s move, play, or turn. I can’t do anything as long as the ball is in John’s court.
See also: ball, court
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • ball's in your court, the
  • the ball is in (one's) court
  • the ball is in court
  • the ball is in someone's court
  • the ball is in your court
  • the ball is in your/somebody's court
  • take charge
  • deep water
  • peril
  • at your peril