Adrien Silva is training with Leicester City, despite Fifa rejecting the Portugal midfielder’s registration.
Paperwork on Silva’s £22m move from Sporting Lisbon arrived 14 seconds too late on the deadline day of 31 August.
Leicester can add Silva to the playing squad when the transfer window reopens in January, but have not ruled out appealing to the Court of Arbitration for Sport against Fifa’s decision.
“He wants to play football and train,” said Foxes boss Craig Shakespeare.
“He’s had to miss out not only on club football but international football and we’ve tried to keep his spirits up.
“I speak to him on a regular basis during training to make sure he’s fully focused on what his requirements are.”
Shakespeare says the club are looking at arranging behind-closed-doors friendly fixtures to help 28-year-old Silva maintain his fitness.
“The camaraderie and the banter is brilliant in and around the changing rooms and I wanted to integrate him as quickly as possible and I can do that now,” added Shakespeare.
“It would be remiss of me not to plan for the worst-case scenario, which is that we don’t have him until January.
“In terms of his fitness, we will have a plan in place – and we will probably have a Plan A, B, C, D, E and F, so it’s something that we will continue to monitor.”