Every one of those concussions doesn't just affect the players while playing, they have long term effects on the players also.
“In February 2011, Dave Duerson, a former NFL safety, aged 50, shot himself in the chest after suffering depression and other serious issues. In a dramatic suicide text message he asked that his brain be sent to Boston University and studied for evidence of chronic neurodegenerative damage or chronic traumatic encephalopathy, thought to be caused by years of concussive impact to the brain. At autopsy it was indeed found that he did suffer from such neurodegenerative disease” (Engelland