The Ghanaian Football Association are to investigate the absence of three key members of their squad for a midweek friendly.
Chelsea midfielder Michael Essien, Inter Milan winger Sulley Muntari and Rennes striker Asamoah Gyan are all set to sit out Wednesday's meeting with Angola.
The trio opted against travelling with their international team-mates for the fixture at the Conqueiros Stadium, but did not have the permission of coach Milovan Rajevic to miss the game and are now in breach of Fifa regulations.
A statement on the GFA's official website from general secretary Kofi Nsiah read: "In accordance with prescribed Fifa regulations for the release of players for national team matches, the FA wrote to and secured the release of 20 players to honour the World Cup qualifying match against Mali on 15th November and the international friendly against Angola on 18th November.
"Unfortunately, three players, namely Michael Essien, Sulley Muntari and Asamoah Gyan, did not travel with the team to Angola on Monday night.
"The players stayed out without the permission of the head coach, Mr Milovan Rajevac. The FA views this act with great concern and will investigate the matter further to inform its next course of action."