He was one of the foundations upon which the Chicago Bears built their legendary defense of the 1980s.
But last week, Dave Duerson, a member of the Bears' 1985 Super Bowl championship squad, killed himself after sending a "bizarre text" to family and friends, pleading with them to donate his brain for study of a debilitating brain injury.
Duerson, who starred at Notre Dame before joining the Bears, was 50. He shot himself in the chest at his home in Florida.
The fatal chest wound allowed his brain to be used for research into chronic traumatic encephalopathy, or CTE.
Duerson's son said he received a "bizarre text" from his father the night before the shooting about the donation of his brain to the NFL's "brain bank."
It isn't yet known if Duerson suffered from CTE, which can be caused by repeated blows to the head and concussions.
Duerson's brain will be examined at Boston University's Center for the Study of Traumatic Encephalopathy for research there on spinal cord and brain trauma.
When former boxers suffer from CTE, it's often said that they're "punch drunk." The disease is believed to afflict football players and boxers toward the ends of their careers, when they suffer severe, repetitive head trauma.
CTE's symptoms include depression, problems with inappropriate behavior and poor judgment, as well as alcohol and drug abuse. Unfortunately, the condition often ends in suicide.
CNN reports that recent studies show that even younger players, still in high school or college, can sustain the kind of traumatic brain injuries that might lead to CTE.
Resource: CNN: "Player's text: Send my brain to NFL research bank": February 21, 2011