World champion Missy Franklin failed to make the 200 metres freestyle final at the Pan Pacific swimming championships on Australia's Gold Coast, despite setting the fourth-fastest time in Thursday's qualifying.
The 19-year-old American, who has been struggling with back spasms in the lead-up to the four-day meet, clocked one minute, 57.63 seconds in her morning heat.
But she was ruled out of the final, to be held Thursday night, because she was the third fastest American and under the rules of the competition, only two swimmers from each country can contest the final.
Franklin's team mate Katie Ledecky, who has set three world records in freestyle swimming in the last two months, was the top qualifier in 1:56.45.
Australia's Melanie Schlanger was second-fastest in 1:57.16 while Shannon Freeland finished third overall in 1:57.40, knocking Franklin out of the final.
Franklin did however rebound to qualify safely for the 100m backstroke final, one of two individual events she won at the 2012 London Olympics. She was third-fastest overall behind Australia's Emily Seebohm, who was the only woman to dip under one minute.
Seebohm finished in 59.72 seconds, while her Australian team mate Belinda Hocking was second fastest in 1:00.46. Franklin was 0.14 seconds further back.
"There is still some discomfort but it is getting much, much better day by day," Franklin said.
Michael Phelps, competing in his first international meet since retiring after London, was scheduled to make his first appearance on Friday.