The stunning revelation by doctors in the wake of the death of Cincinnati Bengals wide receiver Chris Henry offered a cautionary tale for all football players.
Henry, who died last December after falling out of the back of a moving truck, had chronic traumatic encephalopathy (CTE), degenerative brain damage as the result of multiple blows to the head.
What surprised doctors was that Henry had CTE despite never being diagnosed with a concussion in three years at West Virginia and five years with the Bengals.
Wisconsin wide receiver Nick Toon didn't follow Henry's case closely. But Toon, who suffered his first concussion during practice last spring, has intimate knowledge of the debilitating effects concussions can cause.
His father, former Wisconsin wide receiver Al Toon, saw his NFL career cut short after eight seasons because of multiple concussions.
"I remember quite a bit," said Nick Toon, a fourth-year junior who graduated from Middleton High School. "Toward the end of his career, I remember specifically after his last concussion he was not himself.
"He was in a dark bedroom with sunglasses on for like a week. It took him a long time to get back to normal."
Nick Toon's concussion, suffered when the back of his head hit the Camp Randall Stadium turf, was diagnosed as mild.
"It messed me up for a while," he acknowledged. "It took me a long time to feel I was able to process things the way I was before and be fast mentally. . . .
"I didn't suffer memory loss like some people. . . . I popped up right away, but once I got to the sideline I got super dizzy and didn't feel like myself. I went to the training room and did all the tests and they concluded I had a concussion."
Nick Toon was not cleared by the UW medical staff to play in the spring game. He acknowledged, however, had it been a regular-season game he would have lobbied to play.
"You've got to listen to the medical staff, but I would have done everything I could have to get onto the field," he said. "You prepare all year to play 12 and hopefully 13 games. You don't want to miss one opportunity during the year.
"But my dad probably would have tried to keep me from playing. He always tells me you only get one brain and you've still got to live your life after football."
Concussions are not to be treated lightly.
In April the NCAA Executive Committee adopted a policy requiring schools in all divisions to institute a concussion management plan that mandates the removal of a player who exhibits signs, symptoms or behaviors consistent with a concussion during practice or games.
In May, the Big Ten Conference Sports Medicine Committee developed a concussion management plan to serve as a guideline for all league schools. As part of that plan, head coaches and players sign a form that stipulates they are responsible for reporting any symptoms.
According to UW officials:
UW athletes before each season are given a test called "ImPACT" to collect baseline data on their cognitive skills. If an athlete suffers a concussion, the pre-injury data can be compared with the post-injury data to provide doctors with an objective measure to determine whether the athlete is ready to resume play.
"The first thing we have to do is educate our kids," coach Bret Bielema said. "I think that is the biggest change I've seen in the last three years - telling kids if you have any type of head injury make sure you tell somebody."
Toon, senior strong safety Jay Valai and senior wide receiver Kyle Jefferson have suffered concussions.
All three acknowledge players cannot practice or play in fear.
"You can't think about it," Valai said. "If you go out there thinking about it you'll play soft. My mentality is that God has a plan for me and whatever happens, happens."
Jefferson suffered two serious concussions, the first against Michigan State in 2007 and the second against Minnesota in 2008.
For Jefferson, the post-concussion symptoms that stand out are: "Not being able to concentrate, not being able to see and the headaches. . . it's the worst feeling in the world."
Jefferson was the first UW player to try out a helmet designed to cut down on the frequency of concussions.
"It's the best thing," Jefferson said. "It has helped me extend my career.
"I'm lucky. Like Nick said, you've got one brain. And without your brain you have no life."
Nick Toon's father played after suffering several concussions despite the risks before finally retiring in 1992. Valai and Jefferson continue to play, just like thousands of football players across the country.
"You think about it," Nick Toon said, "but it's part of the game.
"When you choose to play the game, that is the choice you've got to make and accept it and live with the consequences."
Explore further: Transgender people pass on health care to avoid social stigma