Brooks Koepka has been baffled by negative responses to him posing for a nude photograph and thinks modern golfers are held to unfair standards.

Four-time major champion Koepka posted an image from his photo shoot for ESPN's Body Issue prior to the start of the Tour Championship at East Lake.

The 29-year-old moved into a one-shot lead over Rory McIlroy and Justin Thomas after two rounds in the race for the FedEx Cup and $15million in prize money.

However, Koepka has been the butt of jokes and while he was able to see the funny side of the photo being placed over the signage for his parking space – apparently by Dustin Johnson – he questioned certain reactions he has seen on social media.

Koepka said: "I've gotten a lot of people on Twitter and Instagram [asking]: 'How in the world could you do this? You never see Arnold Palmer or Jack Nicklaus and guys like that doing that.'

"It blows my mind; golf is the only sport where you're compared to guys from other generations and how they acted, not where they are on the golf course. Golf is pretty weird that way.

"If they had social media back then, I think it would be a lot different for them, too.

"I couldn't care less what people say online. If you've got people hating you, you're doing something right."