The National Football League has just lost another player and, once again, injury and age have nothing to do with it. John Moffitt announced yesterday that he’s quitting the Denver Broncos. Immediately.

“I think it's really madness to risk your body, risk your well-being and risk your happiness for money,” Moffitt told The Associated Press. “Everybody, they just don't get it and they think it's crazy. But I think what I was doing is crazy.” Moffitt says he doesn’t want to be a “poster boy” for anti-football crusaders. Too late for that. The fact is he just told the NFL to take its meat-pulverizer of a job and shove it.

This is every bit as striking as Jonathan Martin leaving the Miami Dolphins after being bullied by his own teammates. Moffitt is not some marginal veteran on a hapless team. He is a 27-year-old guard for the 7-1 Broncos. Having devoted his life to football, he is now quitting halfway through his third season, leaving more than $1 million in guaranteed income on the table.

Martin left the Dolphins in a state of emotional distress. Moffitt seems to be at peace. This may have something to do with his spending the past two years studying the writings of the Dalai Lama, which must have made for some amusing conversation in the Broncos locker room. (How’s this for a motivational half-time speech? “Our prime purpose in this life is to help others. And if you can’t help them, at least don’t hurt them.” No? How about: “Through violence, you may ‘solve’ one problem, but you sow the seeds for another.”)

Both players are walking away from riches and glory for the same reason: Because football is a violent game. In Martin’s case, it was the brutal culture that drove him away. (His teammate Richie Incognito may be the official villain in the bullying story, but the team's coaches never discouraged his behavior.) Moffitt’s departure was spurred by the violence itself, and its potential to inflict long-term damage on him.

It’s not exactly a revelation that football is a violent, dangerous game, but fans are only starting to learn just how violent, just how dangerous. Another former Bronco, Nate Jackson, offered up a graphic account of life in the NFL in his recent memoir, the title of which says it all: “Slow Getting Up.” For further confirmation, consider Washington Redskins safety Brandon Meriweather, who has vowed not to change his style of play despite being suspended for deliberate helmet-to-helmet hits.

In Moffitt, we have a player in the prime of his career who could very well be bound for the Super Bowl this year. Instead, he's walking away from the game mid-season, saying his job is “crazy.” It’s increasingly difficult to reach any other conclusion.

(Jonathan Mahler is a Bloomberg View columnist. Follow him on Twitter.)