Perhaps does bring in police for important game (7)
I believe the answer is:
decider
'important game' is the definition.
(I've seen this before)
'perhaps does bring in police' is the wordplay.
'perhaps does' becomes 'deer' (I've seen this before).
'bring in' indicates putting letters inside.
'police' becomes 'cid' (**).
'deer' placed around 'cid' is 'DECIDER'.
'for' is the link.
(Other definitions for decider that I've seen before include "Ultimate goal" , ""Golden goal", for example" , "Important match" , "Extra period of play to settle a draw" , "Umpire" .)