I think that you are mistaking PTSD for TBI: Traumatic Brain Injury. The latter can cause all sots of issues that are, is some small way, similar to those associated with PTSD, but the two are, in the end, quite different. TBI can cause personality issues, short-term memory issues, and anger as a result of the frustrations it can cause.
I have PTSD. Despite claims to the contrary, it cannot be cured, just managed. TBI is similar in that vein. Both can make life difficult, but I just don't see the possibility of football causing PTSD . PTSD is the result of participating in traumatic events. TBI is the result of physical trauma, period.