A starting lineman at University of Michigan just left the team before his senior year. Not quite the same thing, but he was going to be a starter and might have had a shot at the NFL. I wonder if a small percentage of younger players are starting to get spooked by the long term health concerns Guys have voluntarily left the sport for health reasons for decades now. The expectation of becoming crippled and dying young has always been there. I think the headlines are a little different but I'm not sure how much the underlying story has changed. I don't recall one like this though. Without doing any research at all, it seems that most of the people that have left the sport have been around for a least a few years, and have had some kind of injury history leading up to it, like Patrick Willis, or just haven't had the expected success, like Jake Locker. This guy had one suspected, but undiagnosed concussion since joining the NFL a year ago and decided to quit based on fear of future injury. That seems to be very unique.