The governing body of Super Rugby will announce the future format of the competition tonight.
It will bring an end to a month of confusion and speculation about the format of the mostly southern hemisphere provincial competition.
SANZAAR, made up of the South African, New Zealand, Australian and Argentinean unions, met in London last month to hammer out a solution to the problems of an over-complicated structure.
The 18-team format, introduced in 2016 after Argentina's Jaguares and the Sunwolves of Japan joined the competition and South Africa's Kings returned, was widely criticised and there were fears the quality of the product was being diluted.
It seems certain that Australia and South Africa will lose one or more teams for 2018 to allow a return to the 15-team competition with the Western Force, Southern Kings and Cheetahs franchises the most vulnerable.