SAN FRANCISCO (AP) Brooks Koepka came into the PGA Championship concerned about a left knee that may or may not require more surgery when he gets a chance to catch his breath.
But that's not what had him sprawled on the ground at Harding Park while a trainer worked on him.
''It was my hip,'' Koepka said.
The two-time defending champion said his hip felt tight when he woke Friday. He worked out and it didn't get much better. And even after he loosened it up, the tightness returned when he was warming up on the range.
His trainer came out on the 12th hole, and then twice more on the back nine, all while Koepka was hanging around the lead by not losing any ground. Any concern going into the weekend?
''Nothing to be worried about,'' Koepka said. ''We'll loosen it up again and it will be a lot better.''
Koepka said his tensor fascia latae - a hip muscle - occasionally gets tight on the side.
''It just kind of moved to the front and tightened up the front and kind of the inside and groin,'' he said. ''Where I really felt it was off 12 tee. It just like locked up, cramped, and I couldn't really do anything with it.''
Marc Wahl, his trainer, came out and stretched his hip and then returned twice more. Koepka isn't sure exactly what he did toward the end, only that it worked.
''The one going into 16, where he yanked on my foot, I don't know what Mark does, but it popped and it felt like it just kind of re-positioned itself, and that's when it felt a lot better,'' Koepka said.
Hey, he's not a scientist. And he said he's not worried about it. Koepka goes into the weekend two shots out of the lead in his quest to win the PGA Championship for the third straight year.