A dispute between Alexis Sanchez's agent Fernando Felicevich and his former partner Pablo Tallarico may delay the Chilean forward's debut for Serie A side Udinese.
Tallarico was Felicevich's partner when the 19-year-old Sanchez was transferred from Cobreloa to Udinese in 2006. The Italian side then loaned the player to Colo Colo of Chile and Argentina's River Plate.
Tallarico has accused Felicevich of taking all the commission that belonged to both men, while Cobreloa president Juan George has called for the transfer to be cancelled over the row.
"Cobreloa officially reports a cheat in the international transfer of Alexis Sanchez, so we demand that the contract is annulled," George said. "We also need the correspondent compensations and responsibilities."
George added that the Chilean Football Association (ANFP) and FIFA should "take the necessary measures in the agent-player policy and forbid the international transfer certificate to be released".
Cobreloa have already sent a formal report to the ANFP president Harold Mayne-Nicholls, who has been asked to forward it to football's world governing body.
As the investigation is likely to run until September 30, Sanchez would be unable to play until that day.
Felicevich maintains that there is no irregularity in this transfer.
"I'm calm because documents have been signed completely," he told Radio Agricultura. "There is no strange thing. All the people involved signed and were paid the respective part of the transaction."
However, the ANFP backed Cobreloa.
"(The Chilean FA) will pay attention to any irregularity, distortion, anti-regulation acts or eventual crimes clubs of this federation might be victims of," an official report stated.
"(The ANFP) will act with full rigor and swiftness looking forward to respect the legal regulations of our country and the national and international rules that manage our activity."
This year, at River Plate, Sanchez played 16 Clausura matches, scoring two goals, but Udinese refused to loan him again for the upcoming season.