I rate Sorensen more than anyone on the forum, probably, but I'd be very hesitant to do this. At least right now.
Sorensen, unless he's turned into a psychopath over the summer, is quite prone to nerve-related errors. And that's at fullback with less direct pressure on him. Granted, he did exceptionally well, taming Eto'o amongst others, but CB will be a different story. Consider also Conte breathing down his neck, the immense expectations to do well on the back of the last two seasons and so forth, plus his lack of playtime there for us to begin with. It's a recipe for disaster - another Criscito story, possibly. Knowing Marotta, he'd probably scapegoat him in January.
It'd be better to integrate him over the next six months (not that we have the leeway to really afford this, anyway), but this presents problems of meshing with Chiellini. Ideally, he'd have been partnered at CB for the entire pre-season to get acclimated. Too late now, I guess.
For now, like it or not, but Barzagli is probably the safest bet we have.