Run with stick, heading off to shop (3,2)
I believe the answer is:
rat on
'shop' is the definition.
(both can mean to betray or inform upon)
'run with stick heading off' is the wordplay.
'run' becomes 'r' (cricket abbreviation).
'with' is a charade indicator (letters next to each other).
'stick' becomes 'baton' (term for a stick or staff).
'heading off' means to remove the first letter.
'baton' with its first letter taken off is 'aton'.
'r'+'aton'='RAT ON'
'to' is the link.
(Other definitions for rat on that I've seen before include "desert" , "shop" , "grass up" , "Betray" , "Give away" .)