AUGUSTA, Ga. --- As Jason Day lay in the bathtub in his rental house on Friday morning, his wife, Ellie, could sense his concern and disappointment about his aching back.
So Ellie Day decided to deliver a message to her husband.
"It's the Masters," she said. "You need to suck it up."
Inspired by his wife's talk, Day fired a 5-under 67 to move into a tie for first place with Francesco Molinari, Brooks Koepka, Adam Scott and Louis Oosthuizen after his second round of the 83rd edition of the Masters.
"She's birthed three children, and I haven't," Day said. "She's a lot stronger as a person than me with regards to pain. ... I was moping around the bathroom. I was down. She was trying to get me ready for today, and ultimately it did."
A day after the Australian considered withdrawing from the tournament because of a back injury, Day had six birdies and one bogey in the second round. He has seven birdies on the par-5s in two rounds, which is tied for most in the field through his first 36 holes.
Day, a 12-time winner on the PGA Tour and 2011 Masters runner-up, said he re-injured his back while bending over to kiss his young daughter on the putting green before Thursday's opening round.
As Day made his way to the first tee, the 31-year-old told his caddie, Luke Reardon, "If this stays the same pain as it was on the putting green, I'll probably end up withdrawing."
After receiving medical treatment from his chiropractor on the course after the first hole and again on the fourth, Day was able to gut out a 2-under 70 in the first round.
Day saw his chiropractor again Thursday night and Friday morning, and spent a lot of his down time icing his back.
"Pain is a funny thing, it goes up and down, and everybody's pain threshold is different," Day said. "Someone that is in a lot of pain might feel, you know, something totally different compared to me, so it's hard.
"Every day I feel like I wake up with some sort of aches, you know, and I think you just kind of learn to live with it and you just go along the way."
Day says he has been bothered by back problems from playing golf since he was 13 or 14 years old.
"Sometimes I wake up and I feel like I'm 50, sometimes I wake up and I feel like I'm 70, and sometimes I wake up and feel like I'm 18 again," Day said. "It just comes and goes, and that's just how it is."
Day has battled back problems for much of this season. He withdrew from the Arnold Palmer Invitational in March after hurting his back after only six holes. He said an MRI revealed that he had an annular tear between the L4 and L5 vertebrae and additional facet joint problems.
Epidurals and injections have helped, but the problems have persisted.
Day said he is willing to try just about anything to alleviate his back problems -- except surgery. Last week, while visiting his trainer in Florida, Day said he lay on the floor of a pilot's lounge at an airport blowing into balloons. The exercise was supposed to get his rib cage into the right place.
"I'm blowing these balloons up, and as you let the balloons go, it sounds like you've let one go, right?" Day said. "So every 30 seconds, I would be letting the balloons out, and these guys are looking at me very strange.
"I'm just doing whatever I can to feel good. So if blowing in balloons is what I need to do to feel good, then I will do it all day long."