He didn't leave in the same years as either Bieber/lewa, but you expect him to leave when he's assumed greater responsibilities, and there is strong possibility of more players leaving. So you're basically tell me, the captain's gonna effectively lead the mass departures? I very much doubt. As for his NT position, I don't know how the coach would take to his situation, but if he continues to perform well, I reckon his loyalty will be rewarded. A quality deemed passé in the present context, but still relevant nonetheless to men of character. Ofc, It could well be proven in time that I erred in my judgement with this one, but on the basis of the evidence there is, both my heart and head says he stays.
Fow now ManU would be better served to cut the incessant overtures wrt BVB Captain, and look more into securing the long-term future of your beloved David de flea. Half your fan-base will most likely commit suicide, if that were to happen.