Tigers' pitcher Dontrelle Willis has suffered a setback in the rehabilitation of his injured right knee, and it is doubtful that he'll pitch in the Majors again this season, according to The Detroit Free Press. He has appeared in one game with Class A Lakeland since being sent down, and it is not known when he will be healthy enough to pitch again. He is 0-1 with a 10.32 ERA in the big leagues this season. He was sent to Lakeland after allowing eight earned runs in a June 9 start against Cleveland.