Leicester City's signing of midfielder Adrien Silva from Sporting Lisbon is up in the air after Fifa rejected the player's registration application for being 14 seconds too late.
The Foxes moved for Silva late on last week's transfer deadline day as a replacement for Danny Drinkwater, who was sold to Chelsea for £35m in the dying hours of the window.
Leicester believed they had sealed a £22m deal for the Portugal international before the deadline, but Fifa says its Transfer Matching System (TMS) indicated that the relevant paperwork was submitted 14 seconds past the deadline.
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They are now in the process of trying to appeal the decision, which means Silva is currently unable to play for the club until the new year.
"We are working with Adrien and Sporting Clube de Portugal to overcome some issues relating to the player's registration and exploring all options to find a resolution," said a Leicester spokesperson.
For an international transfer to be ratified, two two clubs involved must enter the key details into Fifa's TMS before their association's deadline — 11pm in England.
If the information matches, an international transfer certificate (ITC) will be issued giving the deal the green light.