Well there's no report on whether it's heat exhaustion or just plain exhaustion from being out of shape.
It could be either one but if I had to put money on it I'd bet on the latter.
Yes he's lost the weight he had from Mini camps but going on a crash plan to shed fat will also play havoc with your strength as well. No matter how you spin it, he's not where he should be right now if he had been dedicated.
He screwed up not doing what is necessary in the offseason and my bet is he's paying for it now and will continue to. If he reacts like a man and fights through it he may come out the football player we all thought he would be. If he dosen't so be it.