Koepka was on a high 12 months ago when he claimed his maiden major victory with a four-shot success at Erin Hills, but he has had a miserable 2018 so far after being sidelined for 15 weeks with a left-wrist injury.
The 28-year-old American did not touch a club for 91 days and missed the Masters before returning to action at the Zurich Classic of New Orleans at the end of April.
He suffered a further scare ahead of The Players Championship and had a precautionary MRI scan and X-ray, but says he is now back to full fitness.
“You go from playing some of the best golf I’ve probably ever played to probably being at the lowest point professionally that I’ve been. It wasn’t easy,” he said.
“The past, I guess, six months, maybe eight months, we kind of knew about the wrist injury a little bit longer than we told people. But I knew it was bugging me and just couldn’t quite figure out what it was.
“Thankfully, we’ve got it situated now where I’m 100 per cent past it. But I’ll tell you what, it was a long four months. It wasn’t anything I’d wish upon anybody.
“I think the lowest point was the fact that I probably gained about 15 pounds. Looking in the mirror wasn’t quite fun. Being in a cast, like a soft cast, and not being able to pick up anything, not being able to do anything.
“But I feel like my body recovers pretty quickly. It’s amazing how strong you can get so quickly.”
Erin Hills, with its wide-open fairways, clearly suited Koepka’s game last year as he triumphed by four shots on 16 under.
Shinnecock Hills is regarded as a completely different type of course, but Koepka does not agree with that opinion.
“To be honest with you, I think they’re actually kind of similar,” he said at his press conference on Tuesday.
“The fairways are obviously not as wide, but I think the fairways out here are pretty generous. I feel like you’ve got, with the second shot, a couple of run-off areas around the greens where you’ve got the option to putt it if you want or you could chip it.
“But it’s like Erin Hills, it’s a second-shot golf course. That’s how I see it. I feel like you’ve got to position your iron play, put it in the right spots, put it below the hole, things like that.
“And to be honest with you, if it keeps firming up the way it has over the last two days, it could be a little links style too. I could see that. Pitching just short of the green, running up, things like that.
“And the wind’s only going to dry it out, but I think there’s rain in the forecast for Wednesday. So it depends how much rain. But I think the golf course sets up somewhat similar.”