As a a raw prospect that needed some polishing, Penning came into a less than ideal situation in terms of scheme. The defenders he was trying to block didn't have to worry about anything but pinning their ears back and hauling it to the passer. Just get to the QB. Elite athletes were allowed to use muscle memory and instinct. Not much thinking going on.
Now those same defenders are being forced to think. Is it another run down my throat? Is it a screen? What is Taysom Hill doing back there? There's another guy going in motion, what's his deal? Wait, do they have that fast WR lined up at RB? What's up with that?
Simply forcing a defense to hesitate for a split second makes all the difference in the world. Not just for Penning but for every single position on offense. Amazing what a little imagination and creativity can do for an offense.