Opening for pro, say, in golf club (6)
I believe the answer is:
putter
'golf club' is the definition.
(type of golf club)
'opening for pro say' is the wordplay.
'opening for' says to take the initial letters.
'say' becomes 'utter' (to utter something is to speak or say it).
The initial letter of 'pro' is 'p'.
'p'+'utter'='PUTTER'
'in' acts as a link.
(Other definitions for putter that I've seen before include "Golf-club" , "Type of golf club" , "Club used on the green" , "Golf club used on greens" , "Club to use on the green" .)