According to reports online, 23-year-old Ning Zetao has been expelled from China's national swimming team and will return to the Chinese Navy team.
National swimming authorities are expected to make an official announcement later on Wednesday.
Ning won a gold medal in the 100-meter freestyle at the 2015 World Championships. At the 2014 Asian Games, he won gold medals in the 50-meter freestyle and 4x100-meter medley and freestyle relays. He also won in the 100-meter freestyle.
He has broken Asian records in two events. Ning also swam for China at the 2016 Summer Olympics in Brazil.