Inexperienced footballer is tender of course (11)
I believe the answer is:
greenkeeper
'tender of course' is the definition.
(a greenkeeper tends a golf course)
'inexperienced footballer' is the wordplay.
'inexperienced' becomes 'green' (similar in meaning).
'footballer' becomes 'keeper' (goalkeeper).
'green'+'keeper'='GREENKEEPER'
'is' acts as a link.
(Other definitions for greenkeeper that I've seen before include "One maintaining a golf course" , "One looking after a golf course" , "One employed to look after a golf course" , "Golf course maintainer" , "Golf course employee" .)