Adrien Silva is now training with Leicester City while the Premier League club consider going to the Court of Arbitration for Sport over his transfer saga.
The Foxes' appeal to FIFA to secure the registration of the Portuguese midfielder was last week 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 £22 million ($29 million, 24 million euros) deadline-day move from Sporting Lisbon was submitted just 14 seconds late.
That request was denied and the 28-year-old will now not be registered to play for Craig Shakespeare's team until January. However, Silva is now being properly integrated into the group.
"I can thankfully report he is training with us," said Leicester boss Shakespeare, whose side resume their Premier League campaign at home to West Brom on Monday.
"Obviously we are disappointed with the decision by FIFA and the other processes are in the hands of the club.
"But he is training with us and I speak to him on a regular basis during training to make sure he's fully focused on what his requirements are.
"Ultimately, he's a footballer and he wants to play football and train and he's had to miss out not only on club football but international football and we've tried to keep his spirits up."
Shakespeare said his aim was to integrate Silva as quickly as possible, adding: "Behind-closed-doors friendlies are something I will look at as regards his fitness. I will talk with Adrien and the club about which way to go forward."