J. League first-division side Sagan Tosu said Monday a player who came down with a fever before their match last weekend against FC Tokyo had tested negative for the novel coronavirus.

The player took a polymerase chain reaction (PCR) test along with the rest of the team as part of the league's scheduled screening program last Friday, on the eve of the match at Tokyo's Ajinomoto Stadium, with all results coming back negative.

After coming down with a fever later that night he was isolated before separating from the team on match day. A subsequent PCR test at a facility in Saga Prefecture also came back negative.

"We've been taking infection control measures that go further than the guidelines, but you can never be 100 percent sure," said Sagan Chairman Minoru Takehara in an online press conference.

FC Tokyo were only notified about the player's condition shortly before kickoff, leading manager Kenta Hasegawa to criticize the league for apparently deciding to proceed with the match before consulting his team.

"I want people to consider what it's like having to play a match where you can't have peace of mind," Hasegawa said.

J. League Chairman Mitsuru Murai on Sunday said the league had made the decision knowing that all Sagan players had cleared the screening on the eve of the match.

"I want to try to dispel any anxiety," Murai said.

The J. League first division resumed on July 4 after a roughly four-month suspension prompted by the novel coronavirus pandemic. All players and staff undergo regular PCR tests as part of safety measures instituted before the restart.