Leicester have been 'forced to reluctantly accept' FIFA's ruling that the Premier League club must wait until January to register Adrien Silva.
The Foxes had agreed a £22 million deal with Sporting CP to acquire the services of the Portugal international on transfer deadline day, but his registration arrived 14 seconds too late.
After FIFA rejected their appeal against the decision, the East Midlands outfit were looking to take their case to the Court of Arbitration for Sport (CAS).
However, those plans have been scuppered by world football's governing body, who are refusing to agree to an expedited appeal from Leicester, leaving Silva in limbo.
The 28-year-old midfielder started training with the first-team squad this month in an attempt to integrate him into their system, but the wait will go on until the new year.
— Adrien Silva (@adrien_silva23) October 2, 2017
A statement from the Foxes read: "It was our intention to submit an application to the Court of Arbitration for Sport for expedited proceedings so that the matter could be resolved as quickly as possible.
"However, it has been made clear to us that FIFA will not support an expedited process, forcing the club to reluctantly accept the single-judge ruling of FIFA's Players' Status Committee without reasonable opportunity for independent arbitration that is timely enough to be effective.
"Our frustration at the denial of effective due process doubles our disappointment at the original outcome and while the club is now essentially powerless to continue to challenge the decision, we will continue to support Adrien in any personal appeal he wishes to undertake.
"We intend to register Adrien at the earliest opportunity. In the meantime, he will remain under our care, training with the squad under the supervision of our coaching, medical and sport science staff."