Right. And history suggests it's rare to see guys average a double double in the Big 12. It's been done by 11 guys in the past decade. Seven of those 11 were first round picks in the NBA. It takes a special player to accomplish that, regardless of the team he's on (all but two of the 11 were also on very good teams).
And Fitzgerald averaged 5 rebounds per game last year. Expecting Osby to come in and double Fitzgerald's production and quadruple the best Osby's ever done himself is probably setting yourself up for disappointment.
I'm pretty sure that I have a better handle on Osby's potential than you do. And besides, I don't have much of an emotional investment in any particular players statistics. So, it will not be either disappointment or elation. I just like watching the kids play.