A few years ago in Durham, NC, at an Enterprise car rental place, I met a guy who played football at Wake Forest and had a brief career in the NFL as a kick returner. We were shooting the breeze about the NFL, and I wish I could remember his name. I told him I was a Bills fan, and he said the moment he decided he didn't want to play football anymore was when he got laid out by London Fletcher on a kick return. He decided the long term physical damage wasn't worth it, plus he was just kind of stringing along anyway, so he bailed.
Edit: I should clarify, he was WORKING at the car rental place. Apparently Enterprise partners with the NCAA and hires a bunch of former athletes.