I don't see anything odd about the pause.
He's a player that could fail a medical. If I was him there is no way I would announce to the world, I'm off to United - arrivederci Juve, unless I already had the scans in my hand that said it was possible. The initial reports from Chile said he needed 4 weeks rest before the knee could be reassessed. We're just about there now. He's due back from training.
I reckon he'll know his options next week and then it'll be back to the question of whether or not we're interested. The English press say no, Mitten says we are if we keep getting the right answers. I'm sticking with the we're interested version.