Yeh they are... I have CT'd a number people with obvious concussions... basically a brain bruise... it shows up lighter grey on CT in area of trauma... to the extent of the bruise and how quickly it heals is another issue and probably depends on severity... in addition his neck got twisted and whiplash I saw someone post earlier can be an issue as well and though probably would stop him from playing, it could throw off his mechanics. I have had both a neither are fun.