The Black Cats played South Korean striker Ji Dong-won in four games earlier this season before realising that he did not have international clearance to play.
Despite this, the Stadium of Light outfit did not face any points deduction.
However, relegated duo Cardiff City and Fulham, along with Norwich City who also face the drop, have joined forces to fight the decision, according to The Observer.
The report suggests that the first steps have been taken to initiate proceedings about the way Sunderland were let off with just a six-figure fine, with a legal letter being sent on behalf of the three clubs arguing their case.
Gus Poyet's side defeated Manchester United 1-0 at Old Trafford earlier today to keep alive their own survival hopes, while condemning both Fulham and Cardiff to relegation.