Chelsea have taken an appeal against a transfer ban to the Court of Arbitration for Sport.
The Europa League champions were banned from signing players by Fifa until the end of January 2020 and the club failed with their first appeal to the world governing body.
It followed an investigation into their signing of foreign under-18 players.
The transfer window closes on 8 August and the Court of Arbitration for Sport (Cas) said "it is not possible" to say when it will make a decision.