Manchester United have told the English FA that Stuart Pearce cannot select any of their over-age players for the British Olympic team apart from Ryan Giggs.
In a telephone conversation with the FA, the club ruled out Team GB coach Pearce picking Rio Ferdinand, Wayne Rooney, Paul Scholes and Jonny Evans for London 2012 as over-23 players.
According to a 2008 court ruling, clubs have the right to refuse to release players for the competition as it is not on the international calendar.
Tom Cleverley, Danny Welbeck, Phil Jones and Chris Smalling could go to the Olympics if they are not picked for England's Euro 2012 squad. United boss Alex Ferguson will not stand in the way of Giggs as the 38-year-old has never played in a major international tournament.
Giggs has indicated he would accept an invitation -- each squad are allowed three over-age players. The prospect of a row, or even a legal battle, looks unlikely.
Ferguson has also barred striker Javier Hernandez from being part of the Mexico Olympic team, saying: "His form last season was fantastic. He's found the second year more difficult, but a lot of that is down to not having a summer break for three years and playing every summer for his country.
"Next season he will be fine as we have agreed with the Mexican FA that he is going to get the rest he needs."
But Hector Gonzalez Inarritu, Mexico's director of the national teams, said that Ferguson has denied permission for Hernandez to participate. Inarritu told a press conference: "Alex Ferguson denied Javier Hernandez's participation in the Olympic games."