Deal maybe when doctor gets into row (6)
I believe the answer is:
timber
'deal maybe' is the definition.
(I know that deal is a type of board)
'doctor gets into row' is the wordplay.
'doctor' becomes 'MB' (abbreviation for Bachelor of Medicine).
'gets into' indicates putting letters inside.
'row' becomes 'tier' (a tier is a row of things).
'mb' inserted into 'tier' is 'TIMBER'.
'when' acts as a link.
(Other definitions for timber that I've seen before include "Wood that's been cut and prepared" , "Wood for building, etc" , "Watch out for falling tree!" , "Warning cry that a tree is about to fall" , "Tree-feller's cry" .)