DeChambeau, who is thought to have gained over nine kilos of weight during the PGA Tour’s three-month coronavirus hiatus, has developed an incredibly aggressive swing that has led to an additional 16.65 metres off the tee.

But Day, speaking from his hotel in Chicago ahead of the BMW Championship at Olympia Fields, says that DeChambeau’s bulked-up body will likely struggle to handle the amount of pressure he is currently putting on it.

“I had a quick chat to him about his body and his swing,” the Ohio-based Queenslander told an Australian teleconference this morning.


“In the short-term I think it's going to be fine. Mid- to long-term I don't think it's going to be. I don't think his body can handle the amount of stress that he's putting on it because not only did he add a lot of weight quickly, he's added a lot of speed very quick, too.

“Now granted, he's a young guy. He seems like he's got a good team around him, so he may be able to handle it a lot better.”

Day, whose own history with weight training restricted movement throughout his swing and eventually aggravated his troublesome back, says he is actively slowing his clubhead speed in order to extend his career. He believes DeChambeau may eventually need to follow suit.

“I'm not 21 anymore. I understand where I'm at in my career in regards to my body, so if I want to add any more years to my career, I have to put in the work,” Day, 32, said.

“I don't think his body can handle the amount of stress that he's putting on it because not only did he add a lot of weight quickly, he's added a lot of speed very quick, too.” – Jason Day

“I may eat my words and Bryson may be out here for 20, 30 more years and still do the exact same thing. But going through what I've done, it can be very difficult to add that weight and try and add that speed very quick.”

“I know that Bryson feels like he knows what he's talking about – and I feel like he knows what he's talking about, too, because every time I talk to him, he's 100 percent confident in what he's doing and he seems like he's healthy, which is a great thing.

“I hope that he stays healthy, and I wish nothing but success for him because he's a guy that everyone is talking about right now. It makes the game exciting. I view him as a friend and as a competitor, but it's pretty impressive to watch what he's done because there's not many people on Tour where people actually stop on the range and watch a guy hit balls like Bryson. So it's pretty impressive.”

Day, who recently parted ways with lifelong coach Colin Swatton, won the BMW Championship when it was held at Conway Farms in 2015 and has arrived at Olympia Fields in solid form, despite missing the cut at The Northern Trust last week.

The 12-time PGA Tour winner had posted four consecutive top-10s prior to his latest effort and has found motivation in trying to regain his position as World No.1.

“I am very motivated to get back to No.1 in the world,” said Day, who was No.1 for 51 weeks between 2016 and 2017.

“My whole purpose in golf right now is to try and get myself back to No.1 because I just don't feel like it's good enough for me to be at 35 in the world.”

Day will be joined at Olympia Fields for the penultimate event of the season by countrymen Adam Scott, Marc Leishman and Cameron Smith.