As has been said umpteen times, Gonzo is a very smart guy...and I'm sure that he is well aware of the risk vs. reward of the situation:
How many more 'Big Ten' hits am I going to take next year? And will that number be greater because teams won't have to focus on guys like Troy, Teddy, Pittman, etc.? What's the chances that one of those hits could be carreer threatening?
Is the rewards of Captaining tOSU during my Senior season worth the extra beating? Will my stock be any greater next year, and is it worth giving up the signing bonus and contract this year to 'gamble' on not getting injured next?
I don't know the answers to those questions in his mind, but you can see how anyone considering both options could easily make the case to go pro.