At an initial stage, organ only played (5,2)
I believe the answer is:
early on
'at an initial stage' is the definition.
I can't judge whether this defines the answer.
'organ only played' is the wordplay.
I cannot quite see how this works, but
'organ' could be 'ear' (the ear is an organ) and 'ear' is present in the answer.
an anagram of 'only' is 'lyon' which is present in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for early on that I've seen before include "not long after starting" , "right at the start" , "Towards the beginning" , "Previously" , "Quite soon in the proceedings" .)