World number one Brooks Koepka has withdrawn from the United States' Presidents Cup team because of injury and will be replaced by Rickie Fowler.
Koepka, 29, re-injured his left knee during October's CJ Cup in South Korea and will miss the event at Royal Melbourne from 12-15 December.
The Presidents Cup sees a US side compete against an international team, excluding European players.
"I regret not being able to compete. I need more time to heal," said Koepka.
"I'm sorry I won't be able to represent the red, white and blue and I wish my team-mates nothing but the best as they work to retain the Presidents Cup.
"I notified captain Tiger Woods that despite constant medical care and rehab, I'm not able to play golf at this time. I consider it to be a high honour to be part of the 2019 team.
"Since my injury in Korea I've been in constant contact with Tiger and assured him I was making every effort to be 100% in time for the Presidents Cup in Australia."
Woods, who had previously stated that overlooking Fowler for a wild card was his "toughest call", added: "Brooks and I talked and he's disappointed he won't be able to compete.
"I told him to get well soon and we're sorry he won't be with us. He would clearly be an asset on the course and in the team room."
Fowler, 30, has finished second or tied second three times in Majors - the 2014 US Open, the 2014 Open and the 2018 Masters - and is currently ranked 21st in the world.
He said: "These team events have been some of the most memorable weeks of my career. To be picked by Tiger to compete with him and the rest of the team is very special.
"It is impossible to replace the world's number one, but I can assure my team-mates and American golf fans that I will be prepared and ready to do my part to bring home the Presidents Cup."
Presidents Cup teams
International: Abraham Ancer (Mexico), Jason Day (Australia), Adam Hadwin (Canada), Im Sung-jae (South Korea), Marc Leishman (Australia), Li Haotong (China), Hideki Matsuyama (Japan), Joaquin Niemann (Chile) Louis Oosthuizen (South Africa), CT Pan (Chinese Taipei), Adam Scott (Australia), Cameron Smith (Australia),
United States: Tiger Woods (capt), Patrick Cantlay, Bryson DeChambeau, Tony Finau, Rickie Fowler, Dustin Johnson, Matt Kuchar, Patrick Reed, Xander Schauffele, Webb Simpson, Justin Thomas and Gary Woodland.