This is the first doping case of the Pyeongchang Olympics.
The news was announced by the Court of Arbitration for Sport, who said that the 21-year-old voluntarily accepted a provisionalsuspension after an out-of-competition test showed signs of acetalozamide, which can be a masking agent and is used as a diuretic.
Masking agents are often used to cover up performance-enhancing substances.
"I have consulted with medical experts to treat any injuries or sickness in advance and I have paid attention to my daily consumption of drinks and food," he said. "I have no merit and motivation for using this drug. I cannot think of any other case than I accidentally and unintentionally took it in," CNN reported, citing Saito as saying, in a statement.
Saito was a reserve on Japan's 5,000-meter men's relay team.
The revelation is a major embarrassment to Japanese sports, which has long prided itself on its clean image and will be hosting the 2020 Summer Olympics in Tokyo.
However, Last month, sprint canoeist Yasuhiro Suzuki admitted to spiking a rival's drink with an anabolic steroid to scuttle his Olympic dream, and was banned for eight years. (ANI)