But it added: "Additionally, both PRO14 Rugby and SA Rugby are in early discussions about potentially expanding the tournament and deepening our partnership to include more South African franchises from 2021."
South Africa rugby body SA Rugby didn't immediately comment on PRO14's announcement.
While no teams have been mentioned, only South Africa's top four, the Bulls, Stormers, Lions, and Sharks, could realistically compete in the PRO14. If any — or all — of them left Super Rugby it would be a body blow to the southern hemisphere club championship, which has been consistently restructured in an attempt to find the best format. South Africa is by far the biggest television audience for Super Rugby.
Teams from Argentina and Japan were brought into Super Rugby in recent years to join South African, New Zealand and Australian franchises in an attempt to expand rugby's reach. But those moves also increased the travel load for teams and the complications in finding the fairest way to decide who actually wins a tournament that is played on three continents. There is not enough time for every team to play the other at home and away.
Super Rugby's latest television rights deal expires this year, giving South African teams a logical window to leave. A move away by South Africa's leading domestic teams might also be a precursor for the world champion Springboks to abandon the annual Rugby Championship — and games against the New Zealand, Australia and Argentina national teams — and play, instead, in Europe's Six Nations.