I just don't see him becoming good enough to have career at Juve.
If, as a centre half, you don't have much pace and you have very limited technique, you need to be pretty close to Chiellini's level of defensive ability and presence to play at a high level.
I could see Sorensen having a good career at a mid-table club or maybe as a back-up at a slightly better club, but don't see him playing at a better level than that in Italy.
So, to me, it's just a question of selling Sorensen when his value is at its highest.
I'm not sure his his value is going to go beyond 10m any time soon.