Blackmon was the Hoosiers' second-leading scorer last season at 15.7 points per game. He finished second on the team with 77 3-pointers.
Coach Tom Crean told The Indianapolis Star on Tuesday that Blackmon was recovering at his home and should be ready to start working out by September. Full team practices aren't scheduled to begin until October.
The injury is a minor setback for a team that has big aspirations after bringing in a top recruiting class.
But the experienced backcourt is supposed to be a key component, too. Kevin "Yogi" Ferrell started all 34 games last season at 1-guard, and Blackmon started 33.