Clinton Portis sat down at a press conference in April 2012 to announce his retirement from the NFL with his two sons smiling next to him. Portis was sad to be leaving the game but happy that his numbers and impact on the game would be remembered by the Redskins, who inducted him into their Hall of Fame. He was also happy that he'd get to spend more time with his kids. A year out, that still hasn't changed.

"To be 31 and retired and spending time with my kids, I love it," Portis told CBSSports.com.

The only question is how long those good times will last, because Portis also discussed receiving numerous concussions during his NFL career.

"The truth is I had a lot of concussions," he said. "It was just the way things were at the time. I'd get hit hard and be woozy. I'd be dizzy. I'd take a play off and then go back in. Sometimes when I went back into the game, I still couldn't see straight. This happened all the time. Sometimes once or twice a game."

How many concussions does he think he had?

"Numerous," Portis said.

Five? Ten?

"More than that, I think," Portis said. "I can't put an exact number on it," he adds. "I just know it was a lot. I stopped counting at some point."

That is a lot of concussions to endure over a nine-year career. Though the science is inexact in terms of the number of concussions to long-term effects, the symptoms of a single concussion can last for over a year. Stacking concussions on top on concussions increases the chances of brain damage. 

His case will be telling for the long-term future of the NFL. If Portis is able to continue living the relatively normal life he currently enjoys in retirement, his decision to leave the game at 31 years old will be wisely replicated by other players. If Portis starts slurring his words and develops suicidal thoughts, it will be a major wake-up call to players and will have serious ramifications towards football as a whole.