As Rory McIlroy prepares for this week's PGA Championship at Aronimink, the four-time major winner is facing more than just the usual tournament pressure. Coming off a disappointing performance at the Truist Championship and dealing with a painful blister on his toe that forced him to cut short his Tuesday practice round, McIlroy has hardly had the ideal buildup to the season's second major.

But according to golf analyst and former PGA Tour player Brandel Chamblee, the 37-year-old's biggest challenge isn't a physical ailment—it's a persistent issue that has plagued him throughout the entire season. While McIlroy has enjoyed considerable success this year, there's one glaring weakness in his game that could derail his quest for a third PGA Championship title.

Speaking on McGinley and Chamblee Live at the PGA Championship, Chamblee pointed to the numbers that tell a troubling story. "When you look at the three events where there is data here at Aronimink—going back to the AT&T in 2010, 2011, and at the BMW—one thing is for sure: the winners weren't the best drivers. They weren't the best iron players. They weren't the best around the greens. But they were unbelievably good on the greens. They were the best," Chamblee explained.

The analysis becomes even more concerning for McIlroy. "With Rory, he has not putted well, for whatever reason, going back to 2015," Chamblee noted. "He would have lost two and a half strokes almost a day, almost five strokes in two rounds. I'll bet you, there are not that many players that would have played all those PGA Championships. Nobody would have putted worse, on average, than Rory."

This season, the stats back up the concern: McIlroy currently ranks 105th in strokes gained putting, making it the weakest part of his game by a significant margin. For a player who already has two PGA Championship victories to his name and dreams of adding a third at Aronimink, overcoming this putting struggle will be crucial. While his blister may heal in a day or two, the bigger question is whether he can find his touch on the greens when it matters most.