Singer, old, is not bad as a player (10)
I believe the answer is:
bassoonist
'a player' is the definition.
(I know that bassoonist is a type of player)
'singer old is not bad' is the wordplay.
'singer' becomes 'bass' (bass is a kind of singer).
'old' becomes 'o' (abbreviation).
'bad' indicates anagramming the letters.
'is'+'not'='isnot'
'isnot' anagrammed gives 'onist'.
'bass'+'o'+'onist'='BASSOONIST'
'as' is the link.
(Other definitions for bassoonist that I've seen before include "Woodwind player" , "Musician" .)