Leicester are considering going to the Court of Arbitration for Sport over the signing of Adrien Silva.
The Foxes' appeal to FIFA to secure the registration of Portuguese midfielder Silva was on Wednesday morning rejected by world football's governing body.
Leicester and the Football Association had asked FIFA to ratify the transfer after the paperwork for Silva's £22million deadline day move from Sporting Lisbon was submitted 14 seconds late.
That request was denied and, as things stand, Silva will now not be registered to play for Leicester until January.