Sports ground finished yard improvement (8)
I believe the answer is:
recovery
'improvement' is the definition.
(recovery is a kind of improvement)
'sports ground finished yard' is the wordplay.
'sports ground' becomes 'rec' (abbreviation for recreation ground).
'finished' becomes 'over' (over can mean finished or ended).
'yard' becomes 'y' (abbreviation).
'rec'+'over'+'y'='RECOVERY'
(Other definitions for recovery that I've seen before include "Retrieval - restoration of health" , "A return to original state, health say" , "Recuperation after illness" , "Act of getting better" , "Green shoots could be a sign of this" .)