The Premier League will block Carlos Tevez's expected move to Manchester United unless they are satisfied the transfer fee will go to West Ham.
The league accepted in April that West Ham had terminated all agreements with Tevez's agent Kia Joorabchian — and will keep a watchful eye on any transfer to ensure that the club keep their promise.
A Premier League spokesman said: "As far as we are concerned any deal to take Carlos Tevez away from West Ham has to be done directly with the club."
The league's stance means that the Argentina striker's proposed move to Manchester United is far from sealed even if they have agreed a deal in principle with the player's representatives.
One possible avenue would be for West Ham to be paid a transfer fee and then agree a compensation figure with Joorabchian for breaching contracts with his company Media Sports Investments (MSI) when they terminated those agreements following their £5.5million fine in April for breaching Premier League rules.
It is understood, though, that the league would want a substantial chunk of the transfer fee to remain at West Ham rather than it all be handed over to MSI in compensation, otherwise they could be accused of merely covering up the third-party agreements that has caused so much controversy.
The details of a deal for the 23-year-old are still unclear because any attempt to sign him on some kind of loan arrangement would be fraught with problems.
Tevez is still under contract for three more years with West Ham.
Given the history surrounding the player, United are certain to go through all the paperwork in minute detail to ensure everything meets Premier League rules.
Tevez, who is currently in Venezuela with Argentina for the Copa America campaign, has been linked to several clubs in England.
He told Argentina newspaper Clarin: "As far as I am aware, I have not received any official offers. Once an offer arrives then we will see. But the fact that Real Madrid, Internazionale and Manchester United are interested in me makes me proud."