Sunderland boss Paolo Di Canio is considering leaving out left-back Danny Rose against Southampton for what would be his last game on loan before he returns to Tottenham.
The England Under-21 star has had an excellent season but is not allowed to play against his parent club in next Sunday's season finale under the terms of his deal.
But Di Canio said: "I have to be careful because if Danny doesn't guarantee me he's really focused, I don't play him.
"I will play Jack Colback because I know he's going to play as a soldier for this club.
"I trust Danny but I don't know him completely."