The duo have already informed Bok coach Heyneke Meyer of their intentions to further their careers abroad.
They are due to leave South Africa at the end of the Super Rugby competition and could be earning more than R500 000 per month playing in the Japanese league.
Negotiations between Olivier, his Japanese club and the Bulls regarding his Super Rugby participation are at an advanced stage. His contract is believed to be for two-years.
Kankowski's stint in Japan is likely to be for six months only. His soured relationship with Sharks coach John Plumtree is believed to have played a part in his desire to leave.
It is unsure if the two will play any part in South Africa's Rugby Championship campaign later in the year.
Both will feature for the Boks in the final Test against England at the Nelson Mandela Bay Stadium on Saturday, with Olivier starting at inside centre and Kankowski providing loose forward cover on the bench.
Kick-off is at 17:00.
Source: media24.co.za
