Geens, 28 years old, is the first Belgian to experience COVID-19 restrictions. He was previously considered a medal candidate.
According to a statement by the Belgian National Olympic Committee, "Jelle Geens contracted corona while he was still training for the Olympic Games in Europe."
"He is completely symptom-free, and has only had one negative test."
"He will make it possible to travel to Tokyo as soon as the rules permit, in order to take part in the mixed relay next weekend. He is hard at work preparing for the start in Europe.
The statement said that Noah Servais was sent to Tokyo as a replacement for Geens if Geens is unable to make it.