TOKYO—Portuguese surfer Frederico Morais has announced that he tested positive for COVID-19 and will miss the sport’s Olympic debut in Japan. Morais, 29, issued a statement on social media Friday evening. “This is likely the saddest video I’ve ever had to post. In 2019 I qualified for the 2020 Tokyo Olympics that were postponed because of COVID-19. And now, because of the virus I won’t be able to compete nor represent my country,” he said in an Instagram video. The Portuguese Olympic team said Morais would not travel to Tokyo as planned. “I was very careful. I have been fully vaccinated for over a month, but I ended up contracting the virus,” Morais said in a statement issued through Portugal’s Olympic team. “I feel fine and I will carry out my isolation. I will be following every second of our team.” The International Surfing Association had no immediate comment but …