“We only wish that he rests in peace now,” he added, thanking medical workers for their care.
A handful of low-ranking wrestlers and trainees as well as a sumo stable master have tested positive for the virus in Japan.
The outbreak has also forced the association to cancel its upcoming tournament, which had been scheduled for this month.
A basho has only been canceled one other time in over half a century, in 2011, over a bout-fixing scandal.
The spring basho, held in March in Osaka, took place without spectators, with wrestlers surrounded by just a handful of judges in the empty arena.
But it was broadcast live on national TV, where viewers could hear sounds normally drowned out by the crowd, including wrestlers slapping their bellies and scraping their feet on the clay ring.
Some rituals were amended, including the traditional ladle of water that a winning wrestler offers to the next in the ring.
There are usually six tournaments across Japan each year and the association says it hopes to hold the one following this month’s canceled basho behind closed doors.
The coronavirus outbreak in Japan has been smaller than in many countries, with around 16,000 cases and 668 deaths confirmed so far, but the government has declared a state of emergency nationwide.