Footballer: tedious exercises still to do? (7,4)
I believe the answer is:
outside left
'footballer' is the definition.
(outside left is a type of footballer)
'tedious exercises still to do?' is the wordplay.
'exercises' is an anagram indicator (letters exercise or move around).
'still to do?' becomes 'left' (still left to do).
'tedious' with letters rearranged gives 'outside'.
'outside'+'left'='OUTSIDE LEFT'
(Other definitions for outside left that I've seen before include "footballer once" , "Winger" , "Forward player" , "Former football field position" .)