Victorian Marc Leishman is in doubt for next week's Masters with wife Audrey placed in an induced coma in an American hospital.
She has pneumonia and was placed in a coma so doctors can pinpoint other serious infections.
Mrs Leishman thought she was battling the flu but, after a visit to urgent care near their Virginia Beach home late Tuesday night (US time).
She posted an update on her Facebook page saying: "Who goes to urgent care suspected flu but ends up getting admitted to the hospital for a various amount of reasons? This girl. Cuddle your babies because I'm really going to be missing mine."
The couple has two young boys, three-year-old Harvey and 18-month-old Oliver.
The Warrnambool star is committed to being by his wife's side, putting his place at Augusta National in jeopardy.
"Our family appreciates everyone's thoughts and concerns," Marc Leishman said.
"We ask that everyone respect our privacy through this difficult period.
"Please keep Audrey in your prayers."
Leishman, 31, was the US PGA tour rookie of the year in 2009 and won his lone title at the 2012 Travellers Championship.
He was tied fourth at Augusta in 2013, when Adam Scott won Australia's first green jacket, having held the opening round lead.
He also led the tournament early in the second round in 2014 before dropping 10 shots in 12 holes to miss the cut on a course he says suits his powerful game.