Doorman for lively ball (7)
I believe the answer is:
bouncer
This clue is a double definition.
'doorman' is the first definition.
(security guard stationed at a door)
'lively ball' is the second definition.
(I've seen this before)
'for' is the link.
(Other definitions for bouncer that I've seen before include "A heavy - ball, say" , "He guards the entrance to nightclubs" , "Club doorman" , "It could be a ball or a chuckerout" , "trampolinist?" .)