Sanfrecce Hiroshima defender Sho Sasaki could sit out another season after re-tearing his right anterior cruciate ligament in training last month.
The 27-year-old underwent surgery on Tuesday to repair the ligament, which he previously tore just four rounds into the 2016 MEIJI YASUDA J1 League campaign.
Sasaki, who joined the club in 2015 from Ventforet Kofu, is expected to fully recover in eight months.