This reminds me of my Sophomore year of high school football. Right after certain hits that year, I would feel what felt like a severe jolt or shock on my left side of my neck shoulder an arm, and I'd have to run off the field for a play or two......and my coach said it was a stinger, so once a week during that season of football, I would go to a chiropractor who would basically re-align my head and neck area.... (it felt like that doc. was going to break my neck each time)...and they would give me some physical therapy in that area for it. Then after that Sophomore season, I played my final two years of high school football without having that issue again. I'm not saying it's the same thing, and I realize NFL collisions are a ton worse than what I experienced, but here's to the hope that he can come back and play again without issues.