Duane could probably do either but I don't think he could do both. Most college programs start going in October and are getting ready for conference tournaments in late December. It would seem there would be quite a bit of overlap. I don't know of anyone who has pulled it off but I am sure there is someone.
It has been a long time ago but I remember watching on TV ex-NFL and KC Chiefs star Curly Culp wrestle and win the NCAA heavyweight title. I think he did that as a senior at Arizona State. Sports might be too specialized to accomplish it today. I think Duane has the physical and athletic abilities to do both successfully in college. Callahan might not like him risking injury but I bet it would be better for his football development for him to wrestle at NU than what he would acccomplish in their off-season workouts. Notice that I am making him a Cornhusker as if it is a done deal.
Did Rulon Gardner do both at Nebraska?