One doesn't work, but might play (7)
I believe the answer is:
striker
'one doesn't' is the definition.
The definition suggests a singular noun which matches the answer.
'work but might play' is the wordplay.
I cannot really understand how this works, but
'work' could be 'strike' (striking is a kind of working) and 'strike' is present in the answer.
A single letter 'r' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for striker that I've seen before include "one who's out?" , "Industrial activist" , "Cricketer facing the bowlers" , "Football attacker" , "One not working" .)