Sort to be grabbed by heartless referee or linesman (5)
I believe the answer is:
rilke
'linesman' is the definition.
(poet Rainer Maria Rilke - someone who wrote lines)
'sort to be grabbed by heartless referee' is the wordplay.
'sort' becomes 'ilk' (ilk can mean a type or kind).
'to be grabbed by' indicates putting letters inside.
'heartless' suggests removing the centre.
'referee' with its centre removed is 're'.
'ilk' placed inside 're' is 'RILKE'.
'or' is the link.
(Other definitions for rilke that I've seen before include "he once wrote" , "Rainer Maria ---, German poet" , "Rainer Maria --, Austrian poet" , "Bohemian poet?" .)