Player gets sack — supporter takes a pee (8)
I believe the answer is:
bagpiper
'player' is the definition.
(bagpiper is a kind of player)
'sack supporter takes a pee' is the wordplay.
'sack' becomes 'bag' (I've seen this before).
'supporter' becomes 'pier' (pier is a type of architectural support).
'takes' is an insertion indicator.
'a pee' becomes 'p'.
'pier' going around 'p' is 'piper'.
'bag'+'piper'='BAGPIPER'
'gets' acts as a link.
(Other definitions for bagpiper that I've seen before include "One blows out air" , "(Scottish) musician" , "Pibroch player" , "Player of traditional Scottish musical instrument" , "Scots musician" .)