Reviled footballer may be Olympic medallist (5)
I believe the answer is:
diver
I believe this is a double definition.
'reviled footballer' is the first definition.
(exaggeratedly diving is frowned upon in football)
'olympic medallist' is the second definition.
(diving is an Olympic sport)
'may be' acts as a link.
(Other definitions for diver that I've seen before include "One jumping off board" , "Cheating footballer" , "Person operating under water" , "One plunges head first into water" , "Underwater worker" .)