Kyle Chalmers is expected to change his mind and race at next month's world titles on an Australian swim team bookended by a schoolboy and 34-year-old.
Australian swimming hierarchy on Sunday night will announce teams for next month's world titles and also the Commonwealth Games starting late July.
The teams will be settled after Sunday's final day of racing at the Australian championships in Adelaide.
Olympic gold and silver medallist Chalmers didn't swim his pet freestyle in Adelaide, opting instead for butterfly over 50 metres and 100m.
Chalmers entered the meet insisting he wouldn't contest the worlds in Budapest and instead focus solely on the Commonwealth Games in Birmingham.
But after winning the 50m 'fly and finishing second in the 100m butterfly, he signalled a change his mind which has yet to be officially announced.
Should Chalmers stick to his plan of missing the worlds, celebrity swimmer Cody Simpson could make his international debut in Budapest in the 100m 'fly - he finished third in the final, with the top-two selected.
Simpson is all but certain of a spot at the Commonwealth Games where Australia can nominate three swimmers for each event.
Australia's teams will feature 16-year-old schoolboy Flynn Southam as a freestyle relay squad member for the worlds and an individual 100m freestyler at the Commonwealth Games.
Southam last month broke Chalmers' 2015 age record for the 100m freestyle and came close to Ian Thorpe's 1999 age record in the 200m freestyle when both swim greats were aged 16.
"It was a just a great experience being here at my first trial meet," Southam said.
"I am just really privileged and grateful ... I have learnt so much.
"In year 12 and 16-years-old, to represent by country ... it's awesome."
At the other end of the age spectrum is Holly Barratt. The 34-year-old sealed selection for the worlds and Commonwealth Games by winning the women's 50m butterfly in Adelaide.
Australian Associated Press
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