Portugal face Spain in the first game of their respective World Cup campaigns with both sides in turmoil.
Four of Fernando Santos' squad have cancelled their Sporting Lisbon contracts following a chaotic season, whilst their rivals are reeling from the sacking of manager Julen Lopetegui on the eve of the tournament.
William Carvalho, Gelson Martins, Bruno Fernandes and Bas Dost joined Rui Patricio and Daniel Podence in filing notice with the Portuguese Securities Market Commission.
Gelson Martins is among the Portugal players to cancel their Sporting Lisbon contracts Spain are also in turmoil after sacking Julen Lopetegui on the eve of the World Cup.
Each player cited 'just cause' in breaking their contracts with Sporting.
One month ago 50 fans broke into the training complex before assaulting players and staff in a shocking end to a tumultuous campaign.
Unconfirmed reports accused controversial club president Bruno de Carvalho of orchestrating the attacks that injured more than one player and destroyed the dressing room.
De Carvalho, who allegedly has links with radical supporter factions, also criticised players on social media during the season.
The situation has since deteriorated hugely and now some of Portugal's most important players have an unwelcome distraction during the World Cup.
William Carvalho is among the players to cite 'just cause' in breaking their contracts They face Spain on Friday, who themselves are floundering after Fernando Hierro was appointed their new boss at the 11th hour.
The announcement of Lopetegui's decision to take over at Real Madrid made his position 'untenable' in charge of the national team and he was sensationally sacked just two days before Spain's opener.
Head of the Spanish FA, Luis Rubiales said: 'We thank Julen for all he has done because he is one of the great people responsible for us being in Russia, but we are forced to dismiss him.
'To win is very important, to have the best coach very important, but above everything is acting in the right way.
Maybe this is tough now, but in the end it will make us stronger.'
An entirely different complexion has been put on the Group B encounter as both teams look to overcome their off-field disarray and kick off the tournament with a win.