Let’s start with what you know about David Montgomery. It’s an advanced metric that seems to have surfaced quite a bit on your Twitter timeline this offseason if you’re a big college football fan:



That’s a “Wow!” stat that makes mere rushing yardage totals feel flat. The Montgomery PFF stat is about toughness, quickness and determination. It’s a bad-ass stat. It seems to get to the core of what makes a running back special.



Thing is, it’s not quite what makes this running back special.



Try to get the Iowa State junior to elaborate on why he’s so great at creating missed tackles and you, too, will come up empty.



“I don’t know,” he says, as if he’s looking right through you. “Some things just happen. I don’t know why. It just happens. I just go out there with the attitude to play hard for the guys around me.”



You try again, teeing him,...