Japan's Olympic judo gold medallist Maki Tsukada has withdrawn from the Doha Asian Games with a calf injury.
Tsukada, winner of the over 78-kilogram title in Athens, was injured in a training session and will need a month to recover, the Japanese Olympic Committee said.
Mai Tateyama will replace Tsukada.
"I feel a little nervous to replace Tasukada," 20-year-old Tateyama told reporters in Doha, and pointed to China's Tong Wen as her main rival.
"She (Tong) is formidable but my aim is to grab the gold medal, " Tateyama said.
Japan won a record eight Olympic judo gold medals in Athens but suffered a setback at the world team championships in September with the men's and women's teams failing to defend their titles.
Kazuro Yoshimura, head of competitive development at the All-Japan Judo Federation, has ambitiously set Japan's gold medal target in Doha at a clean-sweep of all 16 judo divisions.