Dundee United have appealed to Fifa after their deadline-day move for Cardiff keeper David Forde was blocked.
Dundee United want Forde to put pressure on Lukasz Zaluska.
Forde's switch fell foul of the Fifa rule that states a player cannot play for a three clubs in the same season.
Cardiff's third-choice stopper played once for them in the FAW Premier Cup and went on emergency loan to Luton.
The switch was vetoed by the Scottish Football Association but furious United boss Craig Levein said: "I've taken it to Fifa to give an answer on it."
Levein wants Forde to keep the pressure on his number one Lukasz Zaluska.
But their attempt to push through the move was blocked by the same 'three-club' rule which has cast doubt on Daniel Cousin's move from Rangers to Fulham.
The paperwork for Forde's transfer was completed before Thursday's midnight deadline so the move could still go through should Fifa, football's world governing body, allow it.
Levein believes an agreement between English Football League clubs, who do not recognise short-term loans between their members as a transfer, means Forde should be free to sign.
Levein said: "I am really annoyed about this.
"David went on an emergency loan from Cardiff to Luton but because they are in the same league structure English clubs have an agreement that it doesn't count as a transfer.
"Because he had already played for Cardiff in a cup tie it has been blocked and our friends at the SFA have refused to recognise the English agreement.
"It's a crazy rule and I don't for the life of me understand it.
"The paperwork has been done before the window closed so if we get the go-ahead it can still go through."
Forde has played just once for Cardiff this season in their FAW Premier Cup quarter-final victory at Welshpool Town last month.
The 28-year-old Irishman had previously played six games for Luton, who he joined on an emergency loan deal in August.