GWANGJU, South Korea — Katie Ledecky, a five-time Olympic gold medalist, arrived for her third world swimming championships in high spirits, fully expecting to challenge her best times because of how well she had trained at a pre-competition camp in Singapore.
Her prospects for a dazzling dress rehearsal ahead of next year’s Tokyo Olympics took a stunning turn Tuesday morning when Ledecky abruptly withdrew from the preliminaries of the 200-meter freestyle, one of the three individual events she won at the 2016 Summer Olympics.
Ledecky has not felt well since arriving last week for the meet in Gwangju, South Korea, said Lindsay Mintenko, the managing director of U.S.A. Swimming’s national team.
“A decision has been made by Team U.S.A. in consultation with Katie, her coach and the team’s medical staff for her to withdraw from the 200-meter freestyle event on medical grounds,” Mintenko said in a statement.
Ledecky, 22, was also scheduled to swim later Tuesday in the final of her best event, the 1,500-meter freestyle, in which she is the top qualifier and the three-time defending champion.
Her participation in that race is also uncertain, Mintenko said in the statement: “These precautionary measures are being taken to ensure her well-being and proper recovery, and to allow her to focus her energy on an abbreviated schedule.”
Ledecky’s stroke looked off in her opening event Sunday, the 400-meter freestyle. She uncharacteristically faltered on the final lap and was passed by Ariarne Titmus, an 18-year-old Australian who handed Ledecky her first defeat in a major international event longer than 200 meters.
Asked afterward if she was struggling with any physical problem, Ledecky said, “No, no, no, no.”
Ledecky did not show up at the pool Tuesday morning and has not been in the water since warming down after her 1,500-meter preliminary swim on Monday.
Greg Meehan, the head coach for the United States women’s team and Ledecky’s club coach, said that doctors had not diagnosed what was ailing Ledecky and that she did not want to make excuses for her lackluster start.
“This is brutal for her not to be competing,” Meehan said. “She’s such a tough competitor, she wants to be here.”
He added, “If we can get her back in the meet at some point, that would be an ideal scenario.”
Ledecky is also scheduled to swim the 800 freestyle and the 4×200 freestyle relay.