World Rugby are prepared to be flexible on the format of the proposed Nations Championship after opposition from players, unions and clubs.
Plans for the new tournament include end-of-year semi-finals and a final.
This means the finalists would play five weekends in a row, which has been strongly opposed on welfare grounds by the international players' union.
However, it's understood taking away the semi-final stage will be mooted at Thursday's crunch meeting in Dublin.
Representatives from all tier-one nations, along with Fiji, Japan and International Rugby Players, will gather this week in the Irish capital for a key summit.
It comes after the English Premiership and the French clubs released a statement detailing their dissatisfaction about being excluded from the talks, and how the new proposals contravene the binding San Francisco agreement of two years ago.
"The San Francisco agreement reached in January 2017 by all stakeholders, including LNR (French Rugby League) and PRL (Premiership Rugby), represented a proportionate structure for all parties with an international calendar adopted until 2032," said a joint statement.
"The professional leagues now seem to be excluded from this new work, even though the World Rugby project would be a major change to the San Francisco agreement for all elements of the professional game, and impact other competitions."
PRL and LNR have also vaguely threatened legal action to protect their position.
"LNR and PRL regret the fact that World Rugby is not fully involving all stakeholders in seeking a consensus and they can only reserve the option to take any action to preserve their rights and competitions," the statement added.
The clubs are also concerned about the prospect of a five-week international block, something "which had been specifically rejected for established annual international competitions".
However, if the semi-final stage of the Nations Championship was to be removed, the maximum number of games a team would play in the autumn block would be four - with a maximum total of 12 over the course of the year.
This would be fewer than many international sides play currently, with numerous unions regularly staging 'out-of-window' Tests to boost profits.
Aside from the issues around player welfare, the Six Nations unions still need to be convinced on whether to embrace promotion and relegation.
However, both England boss Eddie Jones and Italy boss Conor O'Shea have voiced their support for the concept over the past few days.
According to the Welsh Rugby Union chairman Gareth Davies, rugby union is at its "most challenging and dynamic time since the game went professional in 1995".
With this in mind, Thursday's meeting promises to be one of the most important of its kind in recent history.
Source: BBC Rugby Union News