Musician needing support to carry piano (5)
I believe the answer is:
piper
'musician' is the definition.
(piper is a kind of musician)
'support to carry piano' is the wordplay.
'support' becomes 'pier' (pier is a kind of support).
'to carry' is an insertion indicator.
'piano' becomes 'p'.
'pier' going around 'p' is 'PIPER'.
'needing' is the link.
(Other definitions for piper that I've seen before include "Highland instrumentalist" , "One playing wind instrument" , "Musician sometimes paid (or pied!)" , "Wind instrumentalist" , "Musician (paid for a tune?)" .)