Gesell, a righty, broke a bone in his left hand during a summer league basketball game Thursday night. The 6-2 guard started 30 games for the Hawkeyes last year and averaged 8.7 points.
Hawkeyes coach Fran McCaffery told ESPN.com's Jeff Goodman that Gesell's injury will mean he'll miss out on playing during Iowa's overseas trip in August. He missed four games last year due to a stress reaction in his right foot.
Iowa went 25-13 last season.