FIFA have been called in to help settle a cash wrangle between Sunderland and Celtic over midfielder Colin Healy.
The 23-year-old Republic of Ireland international, whose contract at Parkhead expired at the end of last season, has agreed personal terms with the Black Cats and completed a medical.
However, a row over whether or not the Wearsiders have to pay compensation for the player is threatening to scupper the deal.
Sunderland claim that FIFA regulations mean they do not, while Celtic are adamant that they are due a payment under an International Football League Board agreement.
Now FIFA have been contacted and the clubs will await a ruling on the situation.
"I can confirm that FIFA has received an initial enquiry regarding training compensation for the player Colin Healy," a FIFA spokesman said.
"However, as the matter is still at a very early stage, it would be premature to make any further statement in this regard."
The issue of compensation for the transfer of young players is covered by FIFA regulation VII.
Article 13 of the regulation states: "A player's training and education takes place between the ages of 12 and 23.
"Training compensation shall be payable, as a general rule, up to the age of 23 for training incurred up to the age of 21, unless it is evident that a player has already terminated his training period before the age of 21.
"In the latter case, compensation shall be due until the player reaches the age of 23, but the calculation of the amount of compensation shall be based on the years between 12 and the age when it is established that the player actually completed his training."
And Article 15 adds: "Compensation shall be paid each time a player changes from one club to another up to the time his training and education is complete, which, as a general rule, occurs when the player reaches 23 years of age."
Sunderland in particular will await judgement with bated breathe with the new season only days away. Their cash problems mean that they could not afford to pay compensation for a player McCarthy sees as a valuable addition.
Ironically, the Black Cats are themselves preparing for a tribunal to decide the level of compensation they are due from Manchester United for 20-year-old French midfielder David Bellion, who left the Stadium of Light for Old Trafford when his contract ran out at the end of last season.