A top football color analyst, who captained a college football championship team and spent five seasons in the NFL, quit his job because he couldn’t stand helping sell a sport in which numerous players, from youngsters to grown men, suffer brain injuries.

After 20 years on the job, Ed Cunningham. 48, quit his job as the college football color analyst for ABC and ESPN back in April. He said:

I take full ownership of my alignment with the sport. I can just no longer be in that cheerleader’s spot. In its current state, there are some real dangers: broken limbs, wear and tear. But the real crux of this is that I just don’t think the game is safe for the brain. To me, it’s unacceptable.

Cunningham started playing football as a high school freshman, then captained the University of Washington’s 1991 national championship team before playing in the NFL for the Phoenix (now Arizona) Cardinals and Seattle Seahawks. Then it was on to broadcasting; for most of the last ten years he has joined play-by-play announcer Mike Patrick for Saturday afternoon games.

Cunningham’s stance against reckless hits and irresponsible coaching decisions that endangered athletes elicited condemnation from fans, coaches and administrators, but he remained adamant. Ten years ago, he was quoted in The New York Times in an article about college players returning to games after sustaining concussions.

But Lee Fitting, an ESPN senior coordinating producer who supervises college football coverage, said of Cunningham, “You could put him on any game, and you knew he’d be rock solid and prepared and opinionated and smart and thoughtful. He was always one guy you never worried about. He’s a consummate professional.”

Patrick told The New York Times:

I could hardly disagree with anything he said. The sport is at a crossroads. I love football — college football, pro football, any kind of football. It’s a wonderful sport. But now that I realize what it can do to people, that it can turn 40-, 50-year-old men into walking vegetables, how do you stay silent? Ed was in the vanguard of this. I give him all the credit in the world. And I’m going to be outspoken on it, in part because he led me to that drinking hole.

Cunningham said he was tired of watching players suffer severe injuries while the sport just continued on its merry way, commenting, “We come back from the break and that guy with the broken leg is gone, and it’s just third-and-8.” He added, “I know a lot of people who say: ‘I just can’t cheer for the big hits anymore. I used to go nuts, and now I’m like, I hope he gets up.’ It’s changing for all of us. I don’t currently think the game is safe for the brain. And, oh, by the way, I’ve had teammates who have killed themselves. Dave Duerson put a shotgun to his chest so we could study his brain.”

Duerson was a teammate of Cunningham’s; he killed himself in 2011. After Duerson’s death, he was found to have suffered chronic traumatic encephalopathy (C.T.E.), which is triggered by blows to the head. The Times notes, “It has been discovered in the brains of more than 100 former N.F.L. players.” Another teammate of Cunningham’s, Andre Waters, also killed himself; he had C.T.E., too.

Hall of Fame linebacker Junior Seau was a third player who had C.T.E. and committed suicide. “This is as personal as it gets,” Cunningham said. “I’m not hypothesizing here.”

C.T.E. can only be completely diagnosed after someone’s death.

Cunningham was grateful for the opportunity to work as a color analyst, saying, “I was being paid a really nice six-figure salary for not a lot of days of work, and a live television gig that, except for non-sports fans, people would beat me up to take. I’m leaving a job that’s great. It’s not kind of good. It’s great.”

When he resigned, Cunningham stated that he had two reasons: to see more of his two sons, ages 3 and 5, and his film and television producer career, which took up much of his time. He helped produce Undefeated, a documentary about an urban high school football team.

Weeks later, he confessed a third reason: his worries over what the sport did to its players. He recalled Stanford quarterback Tavita Pritchard getting injured against Notre Dame years ago; and also a more recent incident: last December’s Outback Bowl, in which Iowa quarterback C.J. Beathard was injured but kept in a game Cunningham said “means less than zero” despite his team getting blown out by Florida, 30-3. He commented, “I know some of the coaches from that team, known them for years. And it was hard for me not to walk down after the game and just say: ‘Dudes, what are you doing? Really? What are you doing?’ These are just kids.”

Al Michaels, the veteran broadcaster, took a different position, telling the Times he had no problem staying in his job: “I don’t feel that my being part of covering the National Football League is perpetuating danger. If it’s not me, somebody else is going to do this. There are too many good things about football, too many things I enjoy about it. I can understand maybe somebody feeling that way, but I’d be hard-pressed to find somebody else in my business who would make that decision.”

Cunnungham has some suggestions for the sport, including no contact before high school; limiting the number of plays per game in which a player may participate, and harsher rules and in-helmet sensors for players who use their heads to tackle. Possibly the most important one: softening the exterior of football helmets.

Cunningham concluded, “I think people are starting to think, What should we do here? You can’t throw out everything. You can’t say it’s all broken. You have to change the paradigm. How should it be different 20 years from now? It’ll be different, and I think quite a bit different. And that’s O.K.”