Fly in the central position at some stage (5)

I believe the answer is:
midge
'fly' is the definition.
(I've seen this before)
'central position at some stage' is the wordplay.
'central' becomes ''mid' (I've seen this in another clue).
'position at' becomes 'g' (I can't justify this - if you can you should believe this answer much more).
'some' indicates the central letters.
'stage' becomes 'leg' (a leg is a stage of a competition).
The middle letter of 'leg' is 'e'.
'mid'+'g'+'e'='MIDGE'
'in the' acts as a link.
Can you help me to learn more?
(Other definitions for midge that I've seen before include "Two-winged fly" , "Small flying insect" , "Small swarming biting insect" , "Dipterous insect, in swarms by water" , "Small person" .)
