As speculation continues to mount about the proposed format around a new expanded Celtic League, the News Letter understands the Irish derbies will be protected.
It is almost certain that the existing Guinness PRO12 will be expanded to a PRO14 from the new season with the tournament being split into two conferences of seven clubs in each.
It has been reported that a deal to include South African sides, Southern Kings and The Cheetahs has been agreed and needs to be legally rubberstamped - likely next week.
Under the proposals the Conferences are expected to be split as follows: Two Irish Provinces, two Welsh clubs, and one each from Scotland, Italy and South Africa.
Each team plays each other home and away within their allocated Conference and also play once against the teams in the other section which gives 19 matches - three short from the previous 22 of the PRO12.
Fans have already bought season tickets and are being short-changed.
However, it is now understood that the derby games will be retained on a home and away basis, which for Irish Provinces means two further matches taking it up to 21 games in total.
Neither Celtic League or Ulster Rugby were able to comment further on the situation - the clubs certainly appear to be as much in the dark as everyone else at this stage.
A formal announcement is expected next week on the proposals - a month ahead of the new season.
It has been reported this week that the new deal is likely to benefit the league to the tune of an extra £6m per season from the South African Rugby Union and additional television income.
The winners of each conference will qualify automatically for the semi-finals, while the teams placed in second and third in each conference will be drawn together in play-offs for the remaining two semi-final places.
The increase in revenue equates to around £500,000 in additional income per season for the existing Irish, Scottish, Welsh and Italian sides in the PRO12.