Much as Team Tachiai had worried, the 2020 Aki Basho will start day one with no Yokozuna present. With the publication of the torikumi (fight card) for days 1 and 2 in the top division, it was clear that both Yokozuna Kakuryu and Yokozuna Hakuho would not participate. In the case of Hakuho, he is a month into recovery from having arthroscopic surgery to both knees, and may in fact be questionable for November as well.
For Kakuryu, it seems to have been a case of injuries (unspecified thus far), along with a worry that he had not been able to train up to Yokozuna fighting level prior to the basho. Some of this he has recently attributed to the ban on degeiko, which the Yokozuna use to spar against the top talent and tune up prior to a basho.
This is the first time in 37 years that all active Yokozuna have been absent from the start of a tournament [EDIT: Akebono, the sole active Yokozuna, was absent from Aki 1994. The 37-year gap applies to more than one active Yokozuna: neither Chiyonofuji nor Kitanoumi started Natsu 1983. -lksumo], and it clearly signals we are deep in the transition period, and in my opinion, both Yokozuna are 12 months or less from hanging up their ropes. We know Hakuho wants to hold on and participate in the Tokyo Olympics, which were postponed from this summer due to the COVID-19 pandemic. Kakuryu is looking to stay in Japan and become an elder in the sumo association, which the NSK seems to support. But he must gain Japanese citizenship first, and with that same COVID-19 outbreak continuing to disrupt civilian and government functions, there is no word on him advancing to that goal.