Like many in the golf world, he had his doubts at first but now he's a believer.
Dubbed 'The Scientist' due to his willingness to test his boundaries and trial new technology, DeChambeau returned to the golf course following the coronavirus hiatus 40 pounds heavier having spent hours in the gym. It was a weight gain that allowed him to hit the ball even further -- DeChambeau comfortably leads the PGA Tour's driving distance rankings.
The revamp reaped immediate rewards for the American, as he won his maiden major, romping to a six-shot victory at Winged Foot Golf Club in Mamaroneck, New York last month.
DeChambeau's success and transformation is described by Thomas as "unbelievable."
"I'm the first to admit that I didn't think it was going to work that well and I didn't necessarily agree with what he was doing," Thomas told CNN Sport's Patrick Snell.
"But he's proven it. He's just won a major at one of the hardest golf courses in the world," added Thomas, who has also been impressed by DeChambeau's putting.
"As far as he hits it, as strong as he's gotten, as much weight as he's put on, he putts the c**p out of it to be perfectly honest.
"He's getting some of us out here to try to find that extra gear. He's going to continue to work hard and try to get stronger."
Thomas is also conscious of getting "stronger," but he's taking it step-by-step.
"You just hope that he [DeChambeua] doesn't hurt himself like a lot of, I guess, other people have trying to get stronger and get fit. But I know that's what I'm doing. I'm trying to get stronger. But most importantly, I'm trying to continue to play injury free."
Golf without fans
2020 has been an extraordinary year for golf. Having had to postpone all tournaments for three months, competitive action has returned but without fans.
The absence of the energy that spectators bring to tournaments is the "hardest part" of playing in the Covid-19 era, according to Thomas.
"We're so fortunate to get to do what we love to do," the 2017 PGA Championship winner explained. "We're getting to do our job still. We're getting to play competitively.
"We have it so much better than a lot of people do and myself and a lot of us, all of us don't take that for granted. And the fact of not being able to play in front of fans, although it's a bummer, things could be exponentially worse.
"So we don't take it for granted. We were happy to be able to do what we love and hopefully bring joy to people at home watching, because that's something that I think we all can't get enough of this year."
For Thomas, the 2020 PGA Tour season has been one of his more productive. He won three events, finished second in two -- including the season-ending Tour Championship -- and third in another.
His most recent victory came at the World Golf Championships-FedEx St. Jude Invitational in August. But the pandemic has taught the 27-year-old Thomas to "appreciate things more."
"I'm so incredibly lucky. And to get to do what I love to do and again, to continue to do what I love to do, I mean, there's so many people out there, even not in Covid times, that don't get the luxury of a lot of things that I and we get to do.
"And during all this and with small businesses struggling and people around the world having a hard time, especially in our country. But I try to get better and I hope I have gotten better of just being more appreciative of what I have. And you never want a pandemic like this to be able to do that but, unfortunately, it's happened and hopefully that's come from it."
Thomas was speaking to CNN Sport ahead of the 2020 edition of the CJ Cup, which has a total purse or $9.75 million. Last year, he won his second CJ Cup title, an event that was first played in October 2017.
Normally played at the Nine Bridges Golf Club on Jeju Island, South Korea, this year's edition was moved to Shadow Creek Golf Course in Las Vegas, Nevada because of the pandemic.
"I have set my goals. I actually set them on the flight out here. Usually I would have done it before the U.S. Open, but it was such a quick turnaround, to be perfectly honest, I just completely forgot."
Although he admits it is a shame that he won't be able to defend his crown at a course where he's had "a lot of success," Thomas says going with the flow is what he's learnt to do in this extraordinary year.
"I think that's something that we're all learning this year, is that you have to make the best with the situation that you have. And the PGA Tour has done an unbelievable job of that this entire year. And Shadow Creek as a backup is about as good as it gets."