The belief that the World Anti-Doping Authority had no right to a "de novo" hearing at the Court of Arbitration for Sport is the key plank underpinning the Essendon 34's appeal of their 12-month suspensions in the Swiss Federal Supreme Court.
AFLPA boss Paul Marsh has confirmed that an appeal would be lodged in Switzerland on Wednesday as to the legality of the hearing which ended up with CAS on January 12 upholding WADA's appeal of the AFL's Anti-Doping Tribunal decision that cleared the Essendon 34 of using the banned substance thymosin beta-4.
Marsh argues that as the AFL Anti-Doping Tribunal was operating under the 2010 doping code, which contained no right to "de novo" hearings, WADA had no right to such a hearing at CAS.
The doping code changed in 2015, while the anti-doping tribunal process was still ongoing.
"From where we sit, the players had an emphatic win at the AFL Anti-Doping Tribunal hearing. WADA and ASADA had the ability to appeal that to the AFL Appeals Tribunal, they didn't do that," Marsh said.
"They had the ability to do that on an error of law, or that it was a grossly unreasonable outcome, and they didn't do that because in our view they didn't think they could actually win.
"Instead they went down a path of a completely new hearing and we believe that they didn't have the right to do that.
"This outcome has negatively affected the players' legal rights, so it's not a technicality, we think that this is a fundamental legal right the players have."
Marsh stressed that the Essendon 34 did not seek an injunction so as not to risk their hefty suspensions spilling over into the 2017 season.
Rather, they are undertaking this course of action to clear their names and Marsh is convinced their appeal has strong grounds.
"We are all optimistic about the prospects, we wouldn't be taking this on and the players certainly wouldn't be taking this on if they didn't think they had reasonable prospects," he said.
"It's difficult to be certain in these types of issues, we've got exceptional lawyers telling us that we have got reasonable prospects."
The AFLPA chief executive revealed that some members of the Essendon 34 weren't immediately enthusiastic about going down the appeal path but stressed that none of them had to be convinced to join the appeal and that they each made their own decision to eventually do so.
"The reason why it took a bit of time for some of them is that the toll this issue has taken has been huge," Marsh said.
"For some of them they were at a point where they just wanted this to end and they were mentally prepared to serve out their suspension.
"I guess as this unfolded and it became clear a number wanted to challenge it, players probably saw it was something they could probably park to one side in their own heads and get on with what they're going to do this year and let the lawyers run this process for them."
Marsh confirmed a Swiss legal team would be running the case for all 34 affected past and current players and they have been advised that the process should be complete in four to six months' time.
While Marsh agreed there was a chance that CAS and/or WADA might appeal the Swiss Federal Supreme Court's decision, further dragging out the saga, crucially he stressed that that hypothetical situation would not affect any of the players' suspensions.
Marsh denied the AFL pressured the AFLPA into not taking the matter any further and rebuffed reports that his organisation were in any way funding the legal costs of the Essendon 34 in the appeal process.
A decision on whether captain Jobe Watson gets to keep his 2012 Brownlow Medal will now almost certainly be indefinitely deferred after the AFL initially desired to resolve the issue at a February commission meeting.
The appeal also means that resolution in the players' compensation claims against Essendon will also have to be put on hold.
