I know Saido has had his attitude problems, they are well documented, and there is no use going over them again. However...
We have seen players do a lot worse and be reintegrated into teams, and go on to recapture their form. This is usually thanks to the manager / head coach having managed him well, and done what was necessary to get the best out of the player.
Pulis is failing in that regard, and there is only so long you can go on blaming the player for that. If the manager has to use him in the team, as Pulis does due to lack of options, then he should be trying to work out how to get the best out of him.