Ryan Broekhoff has withdrawn from the Boomers' Olympic basketball selection camp citing mental health struggles while Isaac Humphries has been ruled out by injury.
The pair were both strong chances to feature in Brian Goorjian's final team of 12 for the Tokyo Games but won't join the extended squad in Los Angeles for a training camp that begins this weekend.
Ben Simmons is yet to confirm if he will chase a medal in Tokyo after a disappointing NBA playoffs exit with Philadelphia.
Broekhoff was a standout for the Boomers at the 2016 Olympics and has considerable European and NBA experience.
But he was below his best in a NBL stint with South East Melbourne this year.
"My mental health is something I have struggled with for a long time and I think it's important for me to put my hand up and admit when things aren't okay and that it is time to seek help," he said.
"To play at this level, the team needs me to be 100 per cent, I can't in all good conscience say that I'm in a place to deliver that.
"Everyone who knows me understands the gut-wrenching decision this is, as representing my country is the highest honour I have had in my career.
I know that Goorj and the team can bring home the gold and I will be cheering them on from home."
Humphries' strong NBL form had him in the mix as a back-up to NBA centre Aron Baynes until a knee injury derailed his campaign.
"It's disappointing for sure, this isn't how I wanted my Olympics campaign to go," he said.
"Playing for Australia in the Olympics is a lifelong dream and I will be making every effort to be ready for selection come 2024."
The squad will be headed by Boomers and NBA veterans Patty Mills, Joe Ingles, Matthew Dellavedova and Baynes, while Simmons' 76ers' teammate Matisse Thybulle is also part of the 19-man squad.
That number now sits at 17 and will be reduced to 15 - a 12-man squad with three emergencies - before they play exhibition games against Argentina, United States and Nigeria next month.
The Boomers are chasing a maiden international medal in Tokyo after finishing fourth at the last World Cup and Olympic Games.
BOOMERS OLYMPIC SQUAD: Aron Baynes, Xavier Cooks, Mitchell Creek, Matthew Dellavedova, Dante Exum, Joshua Giddey, Christopher Goulding, Josh Green, Joe Ingles, Nicholas Kay, Jock Landale, Patty Mills, Brock Motum, Duop Reath, Ben Simmons, Nathan Sobey, Matisse Thybulle