European competition appears set to disintegrate further with England's clubs confident the Welsh regions will join them next season.
Premiership Rugby has nine vacant weekends to fill for 2014-15 after announcing on Thursday that the 12 Aviva Premiership teams would not participate in the Heineken Cup.
It is expected that the four Welsh regions will sign up to a cross-border competition with their English counterparts, Press Association Sport understands.
Whether that takes the shape of an enlarged Premiership is undecided with the prospect of promotion and relegation a potential sticking point for the Ospreys, Blues, Scarlets and Dragons.
The Welsh regions would also want assurances that should they withdraw from the RaboDirect PRO12 and Heineken Cup, it would be for a long-term alternative.
The quartet are holding talks with the Welsh Rugby Union next week and are prepared to take legal action against any attempt to prevent them from joining a cross-border competition.
Should they exit the Heineken Cup, only Irish, Scottish, French and Italian teams would be left in the devalued tournament.
There is a view among the Premiership clubs that the Welsh are their natural partners and ties between the parties at boardroom level are close.
The prospect of linking up with South African provinces for 2014-15 is attractive on several fronts, but the far more likely option since the Rugby Champions Cup was abandoned will involve the Welsh.
Knowing the legal hold the French Rugby Federation has over its clubs, Premiership Rugby understood the five Top 14 owners driving their side of the Anglo-French breakaway might be unable to deliver.
Supported by its close relationship with broadcaster BT Sport, which has been fully involved in the process, it looked at an alternative option as soon as it served notice in June that it would not participate in any competition run by European Rugby Cup.
Having pulled the plug on the Rugby Champions Cup last week, France's clubs stated that they will withdraw from the Heineken Cup if the English are absent.
Ligue Nationale de Rugby, the body that represents the Top 14 sides, is aware of Premiership Rugby's announcement that it will not be involved.
However, president Paul Goze has refused to comment on the development as talks over the LNR's agreement with the FFR take place on Friday.
Gloucester director of rugby Nigel Davies believes it would be a natural fit for the Welsh regions to join the Premiership.
"Take the Welsh regions out of the Celtic League and that causes a whole host of problems," Davies said.
"But in terms of coming into an English system, or an Anglo-Welsh system, it's got a lot of merit. Commercially there are a lot of opportunities.
"A Welsh-English club tournament is very attractive to many people. A broad support base would want that, there's the old rivalry there.
"It would work from the supporters' point of view whereas the Celtic League doesn't, certainly for away supporters."