Sunderland manager Martin O'Neill has criticised James McClean for his Twitter outburst during the international break.
McClean apologised to Republic of Ireland manager Giovanni Trapattoni for his comments after being left on the bench during the victory over Kazakhstan last Friday night.
"James has been acting rather strangely," O'Neill said. "It's good when the player not only wants to play but he also wants to manage the team as well.
"He has taken himself off Twitter but he might have a situation with Facebook as well. He has a bit of a problem and we will have to rectify it. Not only that but some of his language was pretty poor and we will have to deal with that.
"James has got to learn about his choice of language, he can't be swearing on these things. He should have a bit more sense – and he has to abide by the set of rules we have here."
O'Neill is expected to fine McClean for breaching club rules on the social networking site.
