Man is rugby forward (6)
I believe the answer is:
rupert
'man' is the definition.
'rugby forward' is the wordplay.
'rugby' becomes 'ru'.
'forward' becomes 'pert' (I've seen this before).
'ru'+'pert'='RUPERT'
'is' acts as a link.
(Other definitions for rupert that I've seen before include "Mary Tourtel's bear" , "It's bought unseen (1,3,2,1,4)" , "Boy" , "Comic strip bear" , "chap" .)