Rousey of course. She's a trained fighter and an NFL cornerback generally isn't. He's taught to defend against fleet footed receivers.
Who wins in a fight, Ronda Rousey or an NFL cornerback?
I vote for Rousey!
As an ex NFLer from many years ago, I would say this all depends on just how much a Gentleman the LB is as I could never hit a female under any circumstance but if this is only hypothetical, the LB would win hands down