"I've been blown away by him when we've been able to hear the conversations he and his caddie have, down the stretch at the PGA or down the stretch in Boston a couple weeks ago," said Jim "Bones" Mackay, Phil Mickelson's long-time caddie who recently took up the microphone. He was referencing two of the five tournament's Thomas has won this season.
"He's the most relaxed guy you've seen in those kind of spots. He looks like he should be playing in shorts and a T-shirt with his buddies for $5, and he's out there trying to win a major."
"He has great belief in himself. A very confident young man. And he should be," Maltbie added.
In building a career that has featured at least one PGA Tour victory each of the last 10 years, a 2016 U.S. Open championship and a current No. 1 world ranking, Johnson also has built the reputation as one of the least outwardly emotional guys on the course. The face on the coin Johnson uses to mark his ball changes expressions more than he does. From a distance, you start to believe, no matter the mess he's in, that his heartbeat has the slow, constant beat of a dripping faucet.
Hit ball far. Lope athletically and purposefully to next shot. Repeat.
As Johnson sees it, why get all worked up about a game?
"I just don't get angry," he said. "If I hit a bad shot I've already seen it before. It's not like it's something new. I've done it a million times. Why would I be mad about it?"
"For me, it's still a game and we're out here to put on a show for all the fans," he said. "And they don't want to see you pitching a fit, that's for sure."
As the sports psychologist will tell you, those who can operate with that attitude under the harshest conditions are the ones we tend to call champions.
"You tell guys, look, most of the greatest players in history were pretty darn calm. They didn't over-react to mistakes. They were kind of like (Ben) Hogan -- the Wee Ice Mon -- cool and calm," Rotella said.