Musician not initially getting support (6)
I believe the answer is:
assist
'support' is the definition.
(assisting is a kind of supporting)
'musician not initially' is the wordplay.
'musician' becomes 'bassist' (I've seen this before).
'not initially' means to remove the first letter.
'bassist' with its first letter taken off is 'ASSIST'.
'getting' is the link.
(Other definitions for assist that I've seen before include "Understand by instinct" , "Provide aid, help out" , "Pass to scorer" , "benefit" , "Aid, abet" .)