Chelsea have appealed to the Court of Arbitration for Sport after being banned for two transfer windows by FIFA.
FIFA issued the ban in February as punishment for Chelsea's transfer of young foreign players.
Chelsea can't sign players during the summer and January 2020 transfer window.
The Premier League club appeal to Fifa to rescind the ban was declined and now they have taken the case to the Court of Arbitration for Sport (CAS).
"The Court of Arbitration for Sport (CAS) has registered an appeal filed by Chelsea Football Club Ltd (CFC) against the Federation Internationale de Football Association (Fifa)," read a statement.
"The appeal is directed against the Fifa Appeal Committee decision dated 11 April 2019 in which CFC was declared liable for violations of the Fifa Regulations on the Status and Transfer of Players and banned from registering new players, nationally and internationally, for two entire and consecutive registration periods," the CAS statement read.
Chelsea is currently facing a dilemma, as Hazard is expected to leave the club with Sarri set to follow.
It will be very hard for Chelsea to get to a top manager with no transfer business going on in the club.
By Ayodele Emaye