He was carried off the field on a stretcher in the 86th minute of the friendly game against Dunfermline on Wednesday evening and was taken to a nearby hospital.
He has a suspected broken collar bone. The injury was sustained during a tussle for the ball just a few minutes before the end of the game. McPake fell awkwardly and damaged his shoulder.
He did walk with assistance in to the ambulance which had arrived by the time the match finished.