Sport in city Den’s abandoned: wise man! (8)
I believe the answer is:
dressage
'sport' is the definition.
(dressage is a kind of sport)
'city den's abandoned wise man' is the wordplay.
I cannot really see how this works, but
'wise' could be 'sage' (similar in meaning) and 'sage' is found in the answer.
'man' could be 'r' (abbreviation for rook, a chess piece or 'man') and 'r' is found in the answer.
The remaining letters 'des' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'in' is the link.
Can you help me to learn more?
(Other definitions for dressage that I've seen before include "Method of training horses to do manoeuvres" , "The training of a horse in manoeuvres" , "Method of horse training" , "Riding skill" , "Equestrian performance" .)