"I know that Matthews has sustained at least two concussions during his years in the NHL. And, while I have no pertinent info, the fact the Leafs are calling it an ‘illness' rather than an injury — and that the issue is complicated by physical exertion — leads me to think he may have taken another shot to the head.
Of course, the NHL has strict concussion protocol and the Leafs would be obligated to keep Matthews out of the line–up if he's experiencing any effects of post–concussion syndrome. I'm sort of debunking my own argument, but no one tells the truth in the playoffs. So we are left to speculate. And, I'm comfortable with the head–shot hypothesis."