Day's strong showing in Augusta makes him one of the favorites when the Wells Fargo opens on Thursday. Rory McIlroy, Justin Thomas and Ricky Fowler, along with Justin Rose, the second-ranked player in the world, are also considered good bets to contend.

Day's health remains a wild card. After more than a decade of dealing with back problems, he's not afraid to try new and different remedies.

"I was explaining the other day that I was blowing into balloons," Day said on Wednesday (Thursday AEST) after playing in the Wells Fargo pro-am. "Which is crazy, because I haven't really trained at all this year because I've been so sore."

Day, 31, who seemed a little embarrassed about the balloon therapy, explained that doing so helps get his rib cage, hips and shoulders aligned, thus alleviating pressure on his back. It's a process that takes 20-to-30 minutes, twice a day.

"Blowing into balloons, that's as far as I go," he said of the therapy. "Long story short, I try to keep my rib cage down. My rib cage gets up and then it blocks my mid back and then I can't really turn. So I get it from somewhere else and that's why my back flares up.

"I've got a guy that I pay and he does a really good job with my back."

The Masters episode wasn't new to Day. He withdrew from the Arnold Palmer Invitational in March, also because of back pain. Over his career, he's also played through thumb and shoulder injuries and had a vertigo attack during the US Open in 2015, when he finished tied for ninth.

"It's hard," Day said of the mental aspects of dealing with injuries. "You have an injury, you feel like your world's ending because this is all you know and this is all you do. You're a professional golfer and this is kind of how you live your life. This is my life. Outside of my family, golf is it.

"Sometimes it's difficult … to ever think, 'Is that the final thing that's going to push me over the line to actually hang up the clubs?' Having a good wife, having a good support system around you, knowing that it's not about right now. It's trying to build to get back to peak performance. That's what you're trying to do."

Like many golfers of his generation, Day was inspired by Tiger Woods. His interest in the sport was piqued when he read a book by Woods while he attended a golf academy. He joined the PGA Tour full time in 2008 and won for the first time in 2010 at the Byron Nelson.

Day's victory at Quail Hollow was his second and final of the 2018 season. He would go on to have fairly pedestrian results the rest of the year. He missed the cut at the US Open, finished tied for 17th at the British Open, tied for 19th at the PGA Championship and 18th at the Tour Championship.

Day is winless thus far this season, but he's been close. He's had five top-10 finishes, including the Players (tie for eighth) and his fifth-place tie at the Masters.

Day was relatively pain free at Quail Hollow in 2018, when he won the Wells Fargo by two strokes over Aaron Wise.

Day had played unevenly for much of the week, but he finished in style, with birdies on the 16th and 17th holes. He hit one of the tournament's all-time great shots on the par-3 17th – which carries a lake – when his tee shot hit the flag stick and settled a few yards from the hole.

"Last year, I was just trying to get it in," Day said. "I felt like as the week progressed, I couldn't quite find the bottom of my swing and couldn't quite find the fairways. Luckily enough, I had my short game to back myself up on it. It was a tough weekend.

"So being able to get through it and push, you always learn something about yourself and see how far you can actually push yourself."

McClatchy