Game casserole almost ruined (8)
I believe the answer is:
lacrosse
'game' is the definition.
(lacrosse is a sport)
'casserole almost ruined' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'ruined' is an anagram indicator.
'casserole' with its last letter taken off is 'casserol'.
'casserol' with letters rearranged gives 'LACROSSE'.
(Other definitions for lacrosse that I've seen before include "Game played with netted sticks" , "Game played with nets on sticks" , "Sport played with sticks" , "Like thirteen of the other clues in the French" , "Score's uncertain after the Spanish" .)