Fix article with nothing to protect it (4)
I believe the answer is:
nail
'fix article' is the definition.
'nail' can be an answer for 'fix' (I've seen this before). I'm not certain of the 'article' bit.
'nothing to protect it' is the wordplay.
'nothing' becomes 'nil' (eg nil is zero in football).
'to protect' is an insertion indicator.
'it' becomes 'a' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'nil' going around 'a' is 'NAIL'.
'with' acts as a link.
(Other definitions for nail that I've seen before include "Fasten, catch (criminal)" , "Brad or tack" , "Collar -- cop" , "Hits this in the head to be bang-on" , "What one has at one's fingertips" .)