I see him training and he looks great, still looks sharp. The problem I have with him coming back is his ability to take damage. His offense has never been an issue, and i believe offensively he's the best in that division and still one of the best in the world, but he can't take a punch anymore.
Age and career length play a huge factor, and getting KO'd when your 21 there's still a great chance you'll recover and come back strong and will be able to take plenty of hard shots in your career. Being as old as he is, I think his chin isn't up to the task anymore. 1- Weidman KO'd him
2- Weidman nearly KO'd him in the 2nd fight from a very short punch when Silva had the clinch.
If he could go in and not get touched, he'd have a great shot, I don't think he can avoid getting hit. And as a result he's going to lose someone who was never at his level.