His work is seen in daily circulation (12)
I believe the answer is:
newspaperman
'his work is seen' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'daily circulation' is the wordplay.
'daily' becomes 'newspaper' (I've seen this before).
'circulation' becomes 'man' (I am not sure about this - if you are sure you should believe this answer much more).
'newspaper'+'man'='NEWSPAPERMAN'
'in' is the link.
Can you help me to learn more?
(Other definitions for newspaperman that I've seen before include "One with editing skill" , "Journalist" , "One of our staff" .)