Keighley are considering taking legal action against the RFL after they were relegated from the Championship at the weekend.
Defeat at home to Featherstone meant the Cougars finished in the fifth and final relegation spot by a single point, with Batley and Whitehaven staying up.
But last month, the Bulldogs were deducted three points for an RFL Operational Rules Tribunal for playing Jacob Fairbank during a win against Sheffield on July 27, only to see them reinstated on appeal.
Cougars chairman Gary Fawcett said: “I spoke to the RFL yesterday straight after the match expressing that we are feeling very hard done to.
“Currently, we are seeking legal advice regarding this problem.
“It is agreed that Doncaster and Batley broke the rules and fielded ineligible players one of which, Jacob Fairbank, scored the winning try for Batley during the game in which he was ineligible.
“For breaching this rule Batley and Doncaster were found guilty and deducted three points by a disciplinary panel which were somehow, miraculously, reinstated the following week and, as far as we know, neither club has been punished at all.
“There is no publicly available information informing us why the points were re-instated. May I remind the reader that, when the same thing happened in football earlier this year (in relation to the Champions League match involving Celtic and Legia Warsaw), the team in question were thrown out of the competition!”