Fifa have been asked to intervene over Celtic midfielder Colin Healy's transfer to Sunderland.
Healy played under McCarthy for the Republic of Ireland
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.
But his transfer has been delayed over whether Sunderland should pay compensation for a player Celtic brought through their youth scheme.
Fifa regulations stipulate compensation should be paid to clubs, who developed players between the ages of 12 and 23.
Healy turned 23 in March, though there remains a grey area involving transfers between English, Irish and Scottish clubs.
Sunderland claim the regulations mean they do not have pay compensation to Celtic, while the Scottish club argue they are due a payment under an
International Football League Board agreement.
"I can confirm that Fifa has received an initial enquiry regarding training
compensation for the player Colin Healy," said a spokesman for the world governing body.
Sunderland's cash problems mean that they might not be able to to afford to pay compensation for Healy.
Sunderland are also preparing for a tribunal to decide the level of compensation they are due from Manchester United for 20-year-old
French midfielder David Bellion.
The Frenchman left the Stadium of Light for Old Trafford
when his contract ran out at the end of last season.