Leicester City's attempts to sign Adrien Silva from Sporting Lisbon were dealt a blow on Wednesday, with FIFA saying it had rejected an FA petition to grant the midfielder an international transfer certificate.

Leicester bought the 28-year-old just before the transfer window closed on Aug. 31, but FIFA, who handle international transfers, received the paperwork moments after the deadline for registration ended.

FIFA refused to sanction Silva's transfer, prompting the English FA to write to the world governing body in early September, but that appeal has now been rejected.

"The petition made by The Football Association for permission to request the International Transfer Certificate for the player Adrien Silva and subsequently register the player for its affiliated club, Leicester City FC, is rejected," FIFA said in a statement.

Leicester will now only be able to sign the player when the transfer window reopens in January, unless they take their case to the Court of Arbitration for Sport (CAS).

A club spokesman said Leicester "were reserving its position" as to whether it would decide to appeal to CAS.

"We cannot hide our disappointment or that of the player at the short-term consequences of the decision," the spokesman added.

"The club and its staff will continue to work with Adrien to hopefully minimise the impact that missing a substantial period of the season may have on the player, while continuing to prepare the squad for the games ahead."