Adrian Mutu has filed an appeal with the Court of Arbitration for Sport against FIFA's ruling that he must pay £13.68million in damages to Chelsea.
Mutu, who cost Chelsea £15million when they signed him in 2003, was told in May that he had to pay the Stamford Bridge club damages for breach of contract.
Chelsea had sacked the Romania striker in 2004 following a positive test for cocaine.
No date has yet been set for a hearing, but Mutu is expected to hear the court's ruling by the end of the year.
"Mutu requests the CAS to annul the FIFA decision and to establish that no compensation is in fact due," read a statement.
Mutu served his ban before signing for Juventus in January 2005. He moved onto current club Fiorentina in 2006.
"It is an unjust and inhumane sentence," the 29-year-old said last month.
"This sanction is not right because I don't think I have committed a crime that merits such an amount."