The Professional Footballers' Association is to intervene in the row between Newcastle and Manchester City over Joey Barton's proposed transfer.
Barton is still waiting to complete his move to St James' Park
Magpies boss Sam Allardyce is furious that the £5.5m switch has stalled over a £300,000 fee possibly owed to Barton.
"I've spoken to City's chief executive Alistair Mackintosh, Joey and his agent and I intend talking to Sam," said PFA official Mick McGuire.
"We're looking for an amicable conclusion," he added.
Barton, 24, is contractually entitled to the pay-off if he leaves the club without requesting a transfer, but City are refusing to give him the money because they say he was not forced to leave.
Allardyce is angry with City for the hold-up and said: "They're out of order. I'm flabbergasted and want the situation resolved.
"I cannot understand it because City didn't pay anything for this player as he came through the youth system and they are selling him for over £5m.
"All I know is that this is a matter for Joey to sort out and I hope it is resolved as it has stopped him putting pen to paper."
West Ham also agreed a fee with City for the England midfielder but after meeting Newcastle officials last month, Barton decided to move to St James' Park.