Obafemi MartinsPosition forwardNationality Nigeria Obafemi MartinsPosition forwardNationality Nigeria 
Ogenyi OnaziPosition midfielderNationality Nigeria 
Oguchi OnyewuPosition centre-back, defenderNationality United States 
Oihane HernándezPosition defenderNationality Spain 
Ola KamaraPosition forwardNationality Sierra Leone, Norway 
Oleksandr SvatokPosition defenderNationality Ukraine 
Olivier MbaizoPosition defenderNationality Cameroon 
Omar BravoPosition forwardNationality Mexico 
Omar CaetanoPosition midfielderNationality Uruguay 
Omar GaberPosition midfielder, defenderNationality Egypt 
Omar GonzalezPosition defenderNationality United States 
Ondřej LingrPosition forwardNationality Czech Republic 
Oniel FisherPosition defenderNationality Jamaica 
Onyekachi ApamPosition defenderNationality Nigeria 
Oriol RosellPosition midfielderNationality Spain 
Oscar DamianiPosition forwardNationality Italy 
Osinachi OhalePosition defenderNationality Nigeria 
Osman BukariPosition midfielder, forwardNationality Ghana 
Osvaldo AlonsoPosition midfielderNationality Cuba, United States 
Osvaldo ArdilesPosition midfielderNationality Argentina