The J-League on Thursday postponed Sagan Tosu's next three league matches after 10 individuals with the first-division side, including manager Kim Myung Hwi tested positive for the novel coronavirus, the league said.
Sagan became the first J-League club to have an infection cluster, of 10 or more positive tests, and has been instructed by public health officials in Tosu, Saga Prefecture, to suspend activities for two weeks.
Sagan was to host Gamba Osaka on Saturday, and play at Vegalta Sendai on Wednesday with another home match against Consadole Sapporo on Aug. 23. No new dates have been announced for those games to be played.
According to the league's coronavirus guidelines, those who have had close contact with infected persons are required to remain at home, even if they have tested negative.
The J-League is now looking to revise its guidelines following the Sagan Tosu outbreak.
"Our main focus is to contain the spread of infection, and not on playing games or training," J-League Chairman Mitsuru Murai said in a statement.
On Wednesday, Sagan's Tosu's Levain Cup group-stage game at Sanfrecce Hiroshima was halted and will not be rescheduled. Neither Sanfrecce nor Sagan would be eligible to advance from the group round regardless of that match's outcome.
In addition to Kim, six players and three members of the team's staff had tested positive by Wednesday, although none had reported any serious symptoms.
In order to stem the spread of the coronavirus, the J-League suspended all official matches from the end of February before restarting at the end of June.