Former NFL center Ed Cunningham announced Wednesday that he resigned from his role as an ESPN college football analyst due to his concern regarding head injuries within the sport.

According to John Branch of the New York Times, Cunningham said the following about his decision to walk away: "I take full ownership of my alignment with the sport. I can just no longer be in that cheerleader's spot."

He also discussed the role concussions played in his unprecedented move: "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 won a national championship at the University of Washington before the Phoenix Cardinals selected him in the third round of the 1992 NFL draft.

He went on to have a five-year NFL career with the Cards and the Seattle Seahawks before becoming an announcer.

Cunningham said he has had his brain tested and showed no signs of damage, but brain trauma hits close to home for him since former teammate Dave Duerson was posthumously found to have chronic traumatic encephalopathy (CTE) after committing suicide in 2011:

"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."

Cunningham told Branch that seeing then-Iowa quarterback C.J. Beathard take numerous big hits in a 30-3 Outback Bowl loss to Florida last season galvanized him to make a change: "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."

Cunningham expressed hope for some fundamental changes to better protect players, including no contact until high school football and limiting players to a certain amount of snaps per game.

With Cunningham out of the fold, ESPN has yet to announce an official replacement alongside play-by-play announcer Mike Patrick for the 2017 season.