Defending 100-metre freestyle world champion James Magnussen has been ruled out of the FINA World Championships in July due to a shoulder injury.
The Australian, 24, will need surgery after losing 70 per cent of the strength in his left shoulder due to "significant damage".
Australia's swim team national head coach Jacco Verhaeren said the decision on Magnussen had been made with an eye to the future.
"It is tough when a swimmer gets to this point and has to withdraw from the national team for such a significant event as the Worlds and especially when you are the defending champion," Verhaeren said of Magnussen, who is set to undergo surgery in Melbourne in early June.
"All indications from our medical staff are that surgery is the best option. If there are any further issues then they can be treated sooner rather than later.
"This will give James more time to have the operation and begin the necessary rehabilitation before starting the preparation for the Olympic cycle.
"He has been recommended two of Australia's finest shoulder surgeons with vast experience in this area and our rehabilitation team at Swimming Australia are already working on ensuring James gets the best possible outcome."
Magnussen, who will need to be replaced in the 50m and 100m freestyle and 4x100m freestyle relay, said he had no other choice but surgery.
"We, as a team, have explored every possible avenue to allow me to compete but unfortunately surgery is the only viable option if I am to be fit for the 2016 Rio Olympics," he said.
"I will now focus all my time and effort on preparing for the Olympics next year. I am looking forward to regaining full strength in my shoulder and getting back to my best performances.
"I wish Jacco and the Dolphins team the best of luck and will be closely following the results."