She was treated at Ohio State University’s cancer hospital and is resting in Columbus, Ohio, where Day and his family live.

“She’s in good hands,” Day said in comments to the Masters website, saying that gave him the peace of mind and confidence to return to golfing.

While his workouts among the Georgia pine trees are a good sign he will play this week in the year’s first major championship, he said that nothing is certain given his mother undergoing chemotherapy treatments.

“Obviously we still have to wait and see – chemo – but we feel much better about things,” Day said.

Day, 29, said in Texas that he could not focus on defending his title over concerns about his mother, who is being looked after by his wife, Ellie, and children Dash and Lucy as well as other family and friends.

“I didn’t even want to be on the golf course,” Day said after withdrawing from the WGC event. “It was a struggle for me to play.”

His mother flew to America from Australia earlier this year.

Day’s time on the course has included work with swing coach Collin Swatton and playing a few holes with compatriot Curtis Luck, the reigning US Amateur champion who makes his Masters debut.

Former world number one Day won his first major title at the 2015 PGA Championship but has 12 other top-10 finishes, including a runner-up effort last year in defending the PGA crown and five top 10s in the past six US Opens, including second-place showings in 2011 and 2013.

Those were the years Day mustered his best Masters finishes so far. Day shared second in 2011, when he led much of the day but lost to four consecutive closing birdies by South Africa’s Charl Schwartzel, and was third alone in 2013, when he led by a shot before bogeys and 16 and 17 and a birdie miss at 18 ended his green jacket bid.

Adam Scott became the first Aussie to win a green jacket, what had been a dream for Day.

“But it’s OK,” he said. “Because I would like to be the second player to win from Australia.”

Day has special reverence for Augusta National, saying “it’s kind of like golfing heaven for us” and adding, “It’s a spiritual place to be able to go and feel it. It’s kind of surreal in a way.”

The course also on Sunday hosted the finals of a national youth competition, the Drive, Chip and Putt Contest. Several past Masters winners were on hand to award prizes.

“Someone who played in the event probably will win the tournament someday and that’s incredible,” 1992 Masters winner Fred Couples said.