After defending his Masters title at Augusta National last month, world No 2 Rory McIlroy would have been hoping to continue his blistering form going into the PGA Championship beginning on Thursday. Instead, the Northern Irishman was forced to halt a practice round for the second Major of the year after only three holes at Aronimink on Tuesday due to a nagging right foot blister. McIlroy said Sunday after limping through the final round of a PGA Tour event at Quail Hollow that he had a blister under his right pinky toenail that began hurting Friday. He insisted it would not be a problem this week, but on Tuesday, McIlroy checked his right shoe several times before taking off his right shoe and sock on the fourth tee and was later taken in a cart back to the clubhouse, ending his first practice round of the week. The 37-year-old, who had a practice round at Aronimink two weeks ago, told Golf Channel he had soaked his right foot on Monday night and removed the right pinky nail to better treat the blister.…