Real Madrid's Copa del Rey opponents Cadiz have filed a formal appeal after the La Liga side fielded an ineligible player in the first leg of their fourth-round tie.
Denis Cheryshev, who scored the opening goal in Los Blancos' 3-1 win, was due to serve a suspension carried over from his loan spell at Villarreal last season after picking up three bookings in the 2014-15 competition.
A statement from Cadiz said: "The RFEF have accepted our appeal and time has been given to Real Madrid to present a defence they deem relevant.
"Cadiz will again show their respect for Real Madrid and their fans and will not make any type of comment until there is an official statement from the Committee of Competition with an edict about the magnitude of what has happened."
It is expected that a decision on Real's future in the competition will be made tomorrow.