FIFA has temporarily suspended the transfer bans imposed two weeks ago on Atletico Madrid and Real Madrid.
The Spanish clubs were notified earlier this month by FIFA that they had been banned from registering new players for the next two transfer windows after they were said to have violated regulations against signing young international players.
Both clubs can now sign players while FIFA makes a determination on the appeal.
The clubs had not been banned from signing players during this current transfer window, but the original sanction applied for the 2016 summer transfer window and the 2017 winter window.
Should FIFA not make a decision on the appeal by the beginning of this summer, both clubs would be eligible to sign players during the 2016 summer window but should the world’s governing body ultimately find that both clubs did violate the regulations against signing young international players, both could be dealt transfer bans for the duration of two windows.