Jason Day has revealed he'll miss the US Open for the first time in his career if his third child is born during the second major of 2018.
The Australian world No.11 said on Friday that his wife Ellie's pregnancy is the reason he's only playing the Australian Open in Sydney this month but not the PGA Championship on the Gold Coast a week later.
Day is yet to find out the due date, but if it were to coincide with the US Open, which takes place from June 14-17, he won't be present at New York's famed Shinnecock Hills course.
Since making his US Open debut in 2011, Day has never missed the event.
"Although I've had some good results at the US Open, Ellie and I are really excited about our third child and I want to be there to support her," Day told AAP.
"I'm not missing the birth."
Day boasts a superb record at the US Open - finishing runner-up twice in addition to three top-10 finishes and will explore every opportunity to be there.
"Once we know the due date, I would have to see what my options are," he said.
"If the baby arrives in the lead up, I may be able to get to the US Open in time."
The Ohio-based Queenslander missed the 2012 British Open to be at the birth of first child Dash and the Australian summer of golf in 2015 for their second child Lucy.
The 29-year-old also confirmed he would not take part in the Hero World Challenge the week after the Australian Open.
The Bahamas showpiece will see 14-times major champion Tiger Woods make his first competitive appearance since February following spinal surgery in April.
The elite 18-man event runs concurrently to the Australian PGA Championship at Royal Pines.
"I have always said family first and given I really wanted to support Australian golf this year and play in the Australian Open," Day told PGA Tour.com.
"That unfortunately means I can't join Tiger and the others at the Hero World Challenge."
