Perhaps one of those who backed Holly in game (7)
I believe the answer is:
cricket
This clue is a double definition.
'perhaps one of those who backed holly' is the first definition.
(the Crickets were Buddy Holly's backing band)
'game' is the second definition.
(I know that cricket is a type of bat-and-ball game)
'in' is the link.
(Other definitions for cricket that I've seen before include "Insect - sport" , "Insect with long leg" , "Six-footer" , "Ball game" , "Summer sport" .)