In the NFL, a safety is the last line of defense. He's that guy who covers a pass and protects the line of scrimmage.
But who's protecting him in a rough and tumble sport where head injuries are all in a days work?
Experts will determine if he was suffering from chronic traumatic encephalopathy. CTE can cause cognitive problems and early dementia and it's most common in people who experience repeated head trauma like pro athletes.
Concussions in the NFL were up 21 percent last year.
Duerson's brain might help doctors see the harm that comes from too many concussions. But more needs to be done to protect professional athletes and provide a little more safety for the safety, tackle, wide receiver and everyone else on the field
That's a page from my notebook.
I'm Katie Couric, CBS News.