He was talked into it because CJ left and he would be a 2 guard.
Look, you can spin it as something different but this is what he said helped him to decide to come back:
"Two things happened this past week that sold Bohannon on his decision, which he called 100% final.
One, CJ Fredrick
transferred out of the program in what was a messy exit to say the least. That left the Hawkeyes without a proven 3-point shooter at the guard position.
Two, McCaffery cranked up his recruiting pitch. Bohannon joked that it felt like his days at Linn-Mar High School again, to have McCaffery selling him on the impact he could have for the Hawkeyes.
McCaffery’s pitch this time? That Bohannon — who has spent almost all of his five years at the “1” (point guard) position — would fit well as a “2” (shooting guard) to complement a young group of guards that includes Joe Toussaint, Ahron Ulis and Tony Perkins."
Why JoBo came back