Partick Thistle have outlined reasons they believe will keep them in the SPL and prohibit Inverness Caley Thistle from being promoted.
Thistle could yet avoid relegation
A letter has been sent to fellow SPL clubs following news of Inverness and Aberdeen's ground-share agreement.
Thistle chairman Tom Hughes maintains they have the law on their side, with Inverness having failed to meet the 31 March deadline.
"The SPL rules have been prejudiced against us," said Hughes.
The SPL clubs will meet on 1 June to decide whether First Division champions Caley Thistle should be promoted.
Thistle, on hearing of the Highland club's agreement with Aberdeen, issued a letter to the SPL, underlining what they believe would be a bending of the rules if Caley Thistle were granted promotion.
In addition to Caley Thistle's failure to meet the 31 March deadline for stadia criteria to be in place, Hughes believes regulations regarding financial assistance have been broken, while ground-sharing is also contrary to Competition Law.
"How can it be right for Aberdeen to start the season around £600,000 better off than Inverness thanks to the groundshare deal and £300,000 up on the
rest of the member clubs?" added Hughes, referring to the cost of ground rental.
Hughes has also asked for clarification of the amount of a parachute payment made to relegated clubs, a figure Thistle believe could be in excess of £500,000.
A ground-share at Pittodrie, necessary because Inverness' Caledonian Stadium does not meet current SPL criteria, will mean a 100-mile drive to Aberdeen for fans of the Division One champions should the SPL accept it.
Caley Thistle won the First Division on the final day
Caley Thistle director of football Graeme Bennett admitted that a minority on his club's six-man board had their doubts, but he believes it is a gamble worth taking for a club that might never get another chance of promotion.
"It has been a difficult time for the club, but I know the support of the fans will be vital to us next season should the SPL approve the groundshare agreement at the monthly meeting on 1 June.
"We would want to play a couple of pre-season games at Pittodrie as a means of getting used to the place and this is an ongoing part of the negotiations with Aberdeen."
Aberdeen chief executive Keith Wyness told his club's website: "We believe this agreement assists both clubs whilst protecting the position of Aberdeen Football Club.
"This agreement is a first for Scottish football and we look forward to a season of collaboration which will benefit both clubs."