Brady you usually smart person, way to give a denial that might as well be a confirmation. If he's never been concussed I doubt he'd weasel-word it the way he did. He's the kind of guy that if he'd never had problems in that area, he'd straight up say so.
So why the weasel words? Probably because he has been concussed and hasn't reported it either because he and the team felt it was too minor to report or because reporting would have meant Brady had to sit out which is a thing he goes out of his way to not do. Either way, if this little soundbite was supposed to shut off this line of quesitoning, that just backfired.