Atwood sees himself as a 3. Iowa looked at him more as a 4 who could swing to the 3 if needed. White was an all-conference 3 last year; Utoff is still too thin for the 4, and Fran may prefer Jok as a guard. Atwood was looked at as a 4 -- and not a guaranteed starter, because it's possible that Fran may have envisioned White at the 4, Utoff at the 3, then Atwood+Uhl off the bench as combo forwards.
He doesn't want to play the 4 -- understandably, because he's undersized for the position, and would get pushed around a bit in the physical Big Ten. He wanted to play in the PAC 12, and he wanted to go where he would be a 3. ASU.