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

the ball is in someone's court

it is that particular person's turn to act next.
This expression is a metaphor from tennis or a similar ball game where different players use particular areas of a marked court.
See also: ball, court