FIFA has given the English Championship club, Cardiff City, a three-window transfer ban threat if they fail to comply with the payment of the first instalment of the transfer fee owed to Nantes for the late Emiliano Sala.
Earlier in September, the FIFA Players' Status Committee ruled in favour of Nantes, the French Club which late Emiliano Sala was leaving to join Cardiff before the unfortunate incident.
The court warns Cardiff to hand over a €6 million (£5.3m) payment for the club-record signing of Sala, who died along with the pilot, David Ibbotson, when their Piper Malibu aircraft crashed in January.
The late Sala had accepted a move but the agreement to pay Nantes £15m was not legally binding due to the negative conditions which were placed by the French club, Nantes.
Cardiff had announced in a statement last month that they will appeal at the Court of Arbitration for Sports, but the world football governing body, FIFA, has outlined its reasons and ordered the Welsh side to pay up.
FIFA, in a 21-page document published on Monday, issued the threat of a ban, which would run through until the end of the 2020-21 campaign, but will be lifted if Cardiff can make the payment within 45 days.
"A ban from registering any new players, either nationally or internationally, for the maximum duration of three entire and consecutive registration periods shall become effective," a section of the judgement read.