Eric could have been hurt on any play because the main problem was that he put his head down. That's the biggest no-no in football and I was almost pissed off watching the play because I knew the injury was avoidable. In fact, in a heated scramble you can hit wrong by mistake - like when NY Jet Dennis Byrd hit his head against another Jet when the QB moved out of the way. EL however ran straight and just put his hat down for some reason.
EL wrote about play in SI:
"I ran downfield after a kickoff and collided with the returner, Malcolm
Brown. I hit him pretty good -- I learned later that he broke his collarbone on the play. But I tucked my head."
http://www.si.com/college-football/2011/10/14/eric-legrand
Over the last years there's been a lot of bad coaching and players often don't train to keep their head up like they should. Dangerous technique will get you hurt faster than certain plays