Justin Thomas won the PGA Championship when he least expected it, matching a tournament record last year at Southern Hills when he rallied from seven shots behind in the final round and won in a playoff.

Now he's not sure what to expect.

That was his only win in the last two years, dating to The Players Championship in 2021. He has fallen out of the top 10 in the world for the first time in nearly six years.

Thomas, who turned 30 last month, is still at No.13 and very much a threat to win wherever he plays. It's just he hasn't felt like that very often over the last year.

"How I described it for a couple months is I've never felt so far and so close at the same time," he said Monday at Oak Hill after playing 18 holes.

"That's a very hard thing to explain, and it's also a very hard way to try to compete and win a golf tournament.

"That's how you get out of it, just playing your way out of it and hitting the shots when you want to and making those putts when you need to, and then your confidence builds back up, and next thing you know, you don't even remember what you were thinking in those times."

Oak Hill looks certain to present as strong a test as Southern Hills was a year ago. Both classic courses had gone through restorations since previously hosting a PGA Championship, and so in some respects, it's new for all 156 players in the field.

Thomas hasn't had the results — only four top 10s since winning the PGA Championship, only one serious chance of winning at the Canadian Open last June — but he is seeing improvement.

Oak Hill last hosted the PGA Championship in 2013 when Thomas was still at Alabama and getting ready to turn pro.

Thomas arrived on Sunday and walked 18 holes to chip and putt. He played with Max Homa on Monday and got the full experience.

"It's everything that I'd heard about. It's a tough test," Thomas said.

"I felt like I had a lot of lies chipping and hitting irons that I had a pretty good idea how it was going to come out, and I didn't. So I think that's going to be something that a lot of people will have to guess correctly or adjust as the week goes on."

The race for No.1 in the world is up for grabs again. Scottie Scheffler had a chance to return to the top spot by winning the Byron Nelson — he finished three shots behind Australian Jason Day, a former PGA champion and world No.1 who is back in form.

Masters champion Jon Rahm remains No.1 and only Scheffler can catch him this week.

For some players, more than a Wanamaker Trophy is at stake this week. The top 60 in the world after the PGA Championship are exempt from qualifying for the US Open. Among those on the bubble is Talor Gooch, world No.63, who has won two of the last three LIV Golf events.