This just doesn't make sense on so many levels, beyond what is sure to be a ludicrous financial offer for him.
Granted, he would not be able to play in the CL, against his former team, no less. However, why would Dortmund sell what is alleged to be an important player, to their direct competition in advancing in the Champions League? That doesn't make any sense at all.
If he is this good, then surely Dortmund would WANT to have him on their squad in the next phase of the CL, would they not?
This makes no sense, and if Juve were to somehow pull this off, I would be a little worried that Dortmund knows something that others do not.