Piece of land is in his league (4)
I believe the answer is:
isle
'piece of land' is the definition.
(I've seen this before)
'in his league' is the wordplay.
'in' indicates the answer is hidden within the clue.
'ISLE' is hidden within 'his league'.
'is' is the link.
(Other definitions for isle that I've seen before include "Man's one" , "Small area of land in water" , "eg Man, Ely" , "Dogs, maybe" , "Eg, eyot or inch" .)