DROPPED BALL

used figuratively to refer to something that did not get handled, because the responsibility for it was not accepted, or correctly passed on, or carried though. Compare the idioms --carry the ball, (American colloquial) to assume responsibility (Webster's New World Student Dictionary), --play ball, to work together; cooperate ( def. 9b Macmillan Dictionary for Students) --keep several balls in the air, you try to do several different things at once and -drop the ball, to make a blunder, to fail in some way [ex - You can't trust John to do the job right. He's always dropping the ball.] (NTC's Dictionary of American English Phrases)