Arm the quarterbacks with a 2 shot .22 derringer.
You get the strategy of knowing how many shots the QB has taken in the game, all sorts of new statistics can be compiled for the fans who like that, and you're more or less guaranteed to have one to four serious injuries per game.
The QB now has to figure out defensive and offensive aiming as well as ball management. Tackles and backers need to factor in taking a shot versus possible possession.
Not to mention that QBs get arrested during most games. There's going to be a lot more substitution.
Really, if you're going to talk about "neutering" the game by making it less dangerous to the players, then obviously it makes the game much more manly if you up the stakes this way.