Despite the Rugby Football Union's insistence Brad Shields will tour South Africa with the England squad in June, New Zealand Rugby appears in a position of legal strength should it choose to block the Hurricanes loose forward.
RFU chief executive Steve Brown yesterday said Shields, set to move to Wasps at the end of the Super Rugby season, is eligible to represent England and will be in the touring party regardless of NZR protests.
This came after NZR previously stated it was under no obligation to release Shields.
Much of the narrative around this complex contracting issue from the UK has centred on World Rugby's regulation nine; the agreement of national unions to release players for international duty during allocated test windows.
"Regulation nine is clear and understood by everybody," Brown told The Times newspaper.
"If we find ourselves in that situation, we will rely on the World Rugby regulation."
Lost, however, has been sub-section 9.38 of World Rugby rules which states, through jargon-filled stipulations, that in circumstances of "dual eligibility, unions may seek a player's written agreement they will not be available for any other nation during the term of their contract".
Born and raised in New Zealand but having not played for the All Blacks, Shields is eligible for England through his parents.
Thus, this situation applies.
Regulation 9.38 states that provided the player in question is older than 18 and had independent legal advice before signing the agreement, "that player shall not be available for selection, attendance and/or appearance in a national representative team or national squad of another union during the term of the written agreement".
And here's the punchline: "During such period the union with whom the player is contracted shall have no obligation to release the player to another union."
This does not necessarily mean NZR will prevent Shields from playing for England in the three tests against the Springboks.
Many have suggested doing so would be spiteful and churlish, given NZR is much more willing to make allowances for players representing the Pacific Island nations.
NZR is, however, understood to be worried about setting a precedent, and appear on safe grounds should they decide to make Shields wait until November to wear the Red Rose.
Throughout the Shields debate, the case of Piers Francis has been cited as an example of NZR allowing a player contracted to the Blues to represent England.
Francis is, however, understood to have not signed the same clause which waives his test rugby rights.
Given these clear guidelines, the RFU's confidence of securing Shields for June seems misplaced.
Shields remains caught in the middle of a messy stoush seemingly destined to be decided in court.
Earlier this week, Shields was asked when the issue would be resolved. The 27-year-old appeared in the dark about much of the details.
"That's something I don't have to worry about," he said.
"My manager and NZ Rugby and whoever else needs to get involved will take care of that. I just want to play good rugby. Those guys can look after the nitty-gritty and fine print. As a player, your goal is to always play at that next level. That's my goal and always has been."