Is it really that big of a deal if that happens once in awhile? I'm probably opening a huge can of worms with this comparison, but NHL players play 3-4 games a week all the time. Granted, both sports are tough as hell on the players.
Football is much more tough than hockey and needs recovery time. Hockey is tough but Football you have running backs/WRs getting hit on every other play. You have the QB getting knocked down 3-5 times a game. The the offensive line is having a pushing and hand war with the defensive line on every single play while playing strategically and covering additional players. The WRs have to sprint on every play. And for special teams you have the opposite team running at you as you run at them.
