One abandoned by players on opponents' ground (8)
I believe the answer is:
castaway
'one abandoned' is the definition.
(thesaurus)
'by players on opponents' ground' is the wordplay.
'by' says to put letters next to each other.
'players' becomes 'cast' (group of actors).
'on opponents' ground' becomes 'away' (I can't explain this - if you can you should give a lot more credence to this answer).
'cast' next to 'away' is 'CASTAWAY'.
Can you help me to learn more?
(Other definitions for castaway that I've seen before include "One shipwrecked in an isolated place" , "Shipwrecked or abandoned person like Robinson Crusoe" , "Stranded person" , ""Captain Bligh"? - with 5d" , "Robinson Crusoe was one" .)