Withdraw from race, disheartened, needing nurse (7)
I believe the answer is:
retreat
'withdraw' is the definition.
(I've seen this before)
'race disheartened needing nurse' is the wordplay.
'disheartened' means to remove the middle letters.
'needing' is a charade indicator (letters next to each other).
'nurse' becomes 'treat' (I've seen this before**).
'race' with its centre removed is 're'.
're'+'treat'='RETREAT'
'from' is the link.
(Other definitions for retreat that I've seen before include "withdrawal" , "asylum" , "Climb down" , "concession" , "Pull back" .)