Quade Cooper says he is "ready and prepared for this journey" after suffering an Achilles injury during Australia's Rugby Championship 41-26 win over Argentina on Saturday.
The fly-half went down injured seven minutes into the second half after slipping while in possession, and grabbed for his left leg before leaving the field with support from medical staff.
Wallabies head coach Dave Rennie revealed after the game that Cooper's injury appeared to be "pretty serious".
The 34-year-old had only just returned from a strained calf that saw him miss the home series defeat to England, and faces a long lay-off just over a year before the Rugby World Cup in France.
Cooper took to Instagram on Sunday to thank his team-mates and medical staff, while vowing to support his team-mates from the sidelines.
He wrote: "Ready and prepared for this journey. Doesn’t mean it will be easy but I know I’ve prepared myself for the challenge ahead by building systems and habits to guide me through each obstacle on my path.
"Prepare for the storm so you are strong enough to endure it.
"Want to thank both my team-mates and the Argentinian players for their support and care when I got injured. My team-mates who continue to help me learn and grow each day I will miss you all but be supporting your journey as I continue mine.
"Our coaches for believing in me and continuing to push my growth. Our medical team who put so much time and energy into each and everyone of us."