This is what getting hit hard, and going right back out on the field will do. These guys are messed up in the head, and they know it, which is why there have been a few cases of the players shooting themselves in the chest and not the head. They want their brains to be studied in order to raise awareness.
Football in general (not just the NFL) is becoming more aware about head injuries and the long-lasting affects of them. A damn shame to see Junior go. He was one guy who I always saw as a straight shooter. RIP.