Want-away defender Gabriel Heinze will take his dispute with Manchester United to a Premier League arbitration panel next week.
A league spokesman confirmed the Argentina international has asked for a three-man panel to decide whether United gave the player permission to leave the club for an agreed fee.
Heinze wants to join Liverpool and claims he has a letter from United allowing him to leave if a club offered a fee of £6.8million.
The club maintain however that they made it clear to Heinze both orally and by letter that he would not be permitted to join one of their title rivals in the top flight.
The three-man panel will be made up of a judge or lawyer, a Premier League representative and a third person experienced in football administration.
Liverpool will have no input at the arbitration panel.
League arbitration panels are reasonably common occurrences and can be called to settle disagreements as minor as a dispute over a fine.
Meanwhile, Heinze, 29, has promised to "carry on like a professional".
The Argentinian met manager Sir Alex Ferguson at United's Carrington training ground on Monday to discuss his future, having confirmed he has brought in lawyers to try to force through a move to Anfield.
But in the meantime Heinze has vowed to continue pre-season training with United.
He told the Daily Mail: "I've fulfilled my duties by returning for training and I will now carry on like a professional. I will keep on coming to training and see what happens. I have a muscle injury in my leg but it is only minor and will not keep me out for long.
"I've spoken with the coach (Ferguson) and I have insisted that my wish is to leave the club if a big offer appears on the table.
"Today the only such offer is from Liverpool and it is this that is causing the problem. Earlier in the summer I received a promise from United that I could leave if the deal was good for both parties and at the moment there is an offer from Liverpool."