Doctor gone -- I'm hoping one returns (6,6)
I believe the answer is:
homing pigeon
'one returns' is the definition.
(a homing pigeon returns home)
'doctor gone i'm hoping' is the wordplay.
'doctor' indicates anagramming the letters.
'gone'+'im'+'hoping'='goneimhoping'
'goneimhoping' with letters rearranged gives 'HOMING PIGEON'.
(Other definitions for homing pigeon that I've seen before include "Trained bird" , "Messenger bird" , "Trained flier" .)