I think Kathy Duva has a pretty good idea of what's going on with Kovalev. I doubt she'd just make something like that up. Frankly I'm surprised she even mentioned it, as using an injury as an excuse isn't exactly an effective way to defend your boxer, especially in such a close disputed decision, but why in the world would she make that statement if there wasn't in fact an injury?
Because Duva is a promoter trying to brush off her fighter losing as pure corruption and an unlucky injury, and not just the fact her guy lost a close fight. Kovalev's stock goes down a lot if his promoter doesn't defend him to the end. And as I have said before, you cannot take anything that idiotic woman says as proof of anything other than mumbo jumbo. She's a complete clown.