Australian five-time Olympic gold medallist Mollie O'Callaghan pulled out of the looming Pan Pacific championships on Saturday due to injury.
The 22-year revealed last month she had spinal stress fractures and had been advised to "stop swimming immediately".
But the reigning Olympic 200m freestyle champion opted to compete at the Commonwealth Games in Glasgow.
She won silver in the 100m freestyle and gold over 200m, although both times were well short of her best.
"I'm incredibly sad that I've made the decision to pull out of PanPacs," she said on Instagram. "I've had to make the decision that is best for me.
"After every race (in Glasgow) I re-evaluated, adapted where I could, and did everything possible to keep moving forward.
"And I'm so proud of what I was able to achieve while managing this injury."
O'Callaghan's absence further limits Australia's star power at the PanPacs in Irvine, California, which start on August 12, with fellow big guns Kyle Chalmers and Cam McEvoy giving it a miss.
Reigning Olympic and world 100m and 200m backstroke star Kaylee McKeown will also be absent after pulling out ahead of the Commonwealth Games citing fatigue and loss of breath.
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