The Senegalese centre-back was a rock at the back in Charlton's fantastic 4-0 defeat of West Ham United.
After picking up a fifth yellow card in the game though, he will now serve an automatic one match ban as a punishment.
Charlton manager Alan Pardew now hopes that one of either Hermann Hreidarrson or new signing Madjid Bougherra will be fit for the Watford game, after both players missed the win over The Hammers because of injury.