Coach Tom Crean called the injury a minor setback.
The school did not release any additional details or a timeframe for Williams' return.
The 6-foot-7 forward signed with Indiana after playing at Oak Hill Academy in Virginia and is expected to be a key contributor on a team that lost four starters from last season, including NBA draft picks Victor Oladipo and Cody Zeller. Indiana has just two seniors and no juniors on this season's roster.
At Oak Hill last season, Williams averaged 16.2 points, 7.5 rebounds, 4.0 assists, and 2.0 blocks.