It doesn't appear as though Andy Pettitte will return to the Yankees before the end of the month. The left-hander suffered another setback in his return from a groin strain and underwent an MRI earlier this week. Pettitte has a "small, persistent strain" of his left groin and will not throw off a mound for at least a week. He originally suffered the injury in the third inning of a start against the Rays at Yankee Stadium on July 18.