Chelsea have been rocked by FIFA's ruling that they will be unable to buy any new players in the next two transfer windows.
World football's governing body decided that the Blues were guilty of inducing French teenager Gael Kakuta to breach his contract with Lens when they brought him to Stamford Bridge.
As a result of the ruling, Chelsea will not be able to register any new players until January 2011.
A statement on FIFA's official website read: "On the occasion of its last meeting held on 27 August, the Dispute Resolution Chamber (DRC) was called to pass a decision in a contractual dispute opposing the French club Lens to the French player Gael Kakuta and the English club Chelsea.
"The French club had lodged a claim with FIFA seeking compensation for breach of contract from the player and requesting also sporting sanctions to be imposed on the player and the English club for breach of contract and inducement to breach of contract respectively.
"The DRC found that the player had indeed breached a contract signed with the French club. Equally, the DRC deemed it to be established that the English club induced the player to such a breach.
"As a result the player was condemned to pay compensation in the amount of Euros 780,000, for which the club, Chelsea, are jointly and severally liable, and sporting sanctions were imposed on both the player and Chelsea.
"A restriction of four months on his eligibility to play in official matches has been imposed on Kakuta. Chelsea are banned from registering any new players, either nationally or internationally, for the two next entire and consecutive registration periods following the notification of the present decision.
"Furthermore, the club, Chelsea, have to pay Lens training compensation in the amount of Euros 130,000."