Here's the quote from James Allen's site:

“He’s not even concussed. The technical definition of a concussion is that you can see it in a scan. The possibility is that the change of direction happened so fast that actually it was like – it’s inappropriate to use the word – a whiplash of the brain. It didn’t actually touch anything. It didn’t bruise, it didn’t bleed.

“I’m not trying to conceal anything. I’m just telling you the facts: he is physically perfect. There is no concussion.”