Another team faces the chop from Super Rugby, and the conference system could be scrapped.
Japan's Sunwolves are the team in greatest danger according to the Sydney Morning Herald, in a report which says a return to the 14-team format was among formats discussed by SANZAAR.
A complicating factor is the cloud over South Africa's four teams, who are rumoured to be interested in joining European competitions.
The Sunwolves finished last in 2018 and despite some strong performances have struggled for overall credibility during four seasons.
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With the competition limited to 22 weeks, a full home-and-away round robin is impossible.
The competition's integrity has been compromised by constant speculation and changes which include chopping it back from 18 teams.
More format changes were considered after World Rugby meetings in Dublin three weeks ago, according to the SMH.
The SMH reported: "...a return to round robin is already widely supported by fans in all three of the major markets (Australia, New Zealand and South Africa), as well as coaches and players.
"The Sunwolves appear to be the team most at risk, unless another South African team follows in the footsteps of the Cheetahs and Kings and joins the Pro 14 (in Europe)."