Minor role in two pieces? (3,4)
I believe the answer is:
bit part
'minor role' is the definition.
(synonyms)
'two pieces?' is the wordplay.
'two pieces?' can mean two substitutions for 'piece'.
'piece' becomes 'bit' (synonyms).
'piece' becomes 'part' (synonyms).
'bit'+'part'='BIT-PART'
'in' acts as a link.
(Other definitions for bit part that I've seen before include "Tiny or non-speaking dramatic role" , "cameo" , "'Small role in film or play (3,4)'" , "Small acting role" , "Tool" .)