The coaches and trainers might not have seen the full stumble. .
It was just so odd that he was back on the field after a couple of plays. Seems even if the trainers didn't see him stumbling around and falling over that someone
would have alerted them to how bad it seemed.
Perhaps the sideline concussion test they administered is absolutely foolproof. However, even with some small chance that it's not it seems they would have at least brought him to the locker room until halftime.
It certainly made for uncomfortable viewing, as I'm sure I wasn't the only one cringing a bit every time he got tackled for the rest of the half. Again, odd considering that concussions are the hot button issue of the moment.