Player putting key in a lock (7)
I believe the answer is:
actress
'player' is the definition.
(actress is a kind of player)
'key in a lock' is the wordplay.
'key' becomes 'c' (I've seen this in other clues**).
'in' indicates putting letters inside.
'lock' becomes 'tress' (I've seen this before).
'a'+'tress'='atress'
'c' going into 'atress' is 'ACTRESS'.
'putting' acts as a link.
(Other definitions for actress that I've seen before include "Casters (anag.)" , "Stage performer" , "eg Emma Thompson" , "Theatrical female" , "Female thespian" .)