Kluber (forearm) was removed after the first inning of Sunday's rehab start for Double-A Akron due to abdominal tightness, Mandy Bell of MLB.com reports.
Kluber's removal was reportedly precautionary, but he'll likely head to Cleveland for further evaluation with the hope he's not dealing with a serious injury. It remains to be seen if this setback will have a major impact on his timetable.