Scout I note runs, following sport on playing field (9)
I believe the answer is:
recruiter
'scout' is the definition.
'sport on playing field' is the wordplay.
'sport' becomes 'ru' (rugby union).
'on' means one lot of letters goes inside another.
'playing field' becomes 'reciter' (I can't explain this - if you can you should believe this answer much more).
'ru' placed within 'reciter' is 'RECRUITER'.
'i note runs following' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for recruiter that I've seen before include "One enlisting others into forces" , "He used to offer a shilling" .)