Manning (shoulder) exited Thursday's rehab start at Triple-A Toledo because he was experiencing lightheadedness, Evan Petzold of the Detroit Free Press reports.
Manning was removed from his third rehab start during the third inning, but general manager Al Avila said that the right-hander didn't suffer an aggravation of the shoulder injury that initially forced him to the 10-day injured list April 20. Thursday's outing was expected to be Manning's final rehab start, but because he threw only 49 pitches before exiting, the Tigers may want him to make another start in the minors before bringing him back from the IL. Regardless, assuming he's able to quickly overcome the bout with lightheadedness, he should be on track to rejoin Detroit's rotation by the end of the month.