Street loves extremely game fall guy (6)
I believe the answer is:
stooge
'fall guy' is the definition.
(I've seen this before)
'street loves extremely game' is the wordplay.
'street' becomes 'st'.
'loves' becomes 'oo'.
'extremely' suggests removing the centre.
'game' with its middle taken out is 'ge'.
'st'+'oo'+'ge'='STOOGE'
(Other definitions for stooge that I've seen before include "Butt of a comic's jokes" , "A comedian's stage butt or straight man" , "Performer who is butt of another's jokes" , "Yes-man" , "Comedian's feed" .)