Martin O'Neill has threatened to drop James McClean after the Sunderland winger's row with the Republic of Ireland manager, Giovanni Trapattoni.
O'Neill has already told the 23-year-old former Derry City winger that he has broken club rules by criticising Trapattoni on the social networking site Twitter after being left out of Ireland's opening World Cup qualifier, a victory over Kazakhstan.
McClean was forced to apologise to Trapattoni and the entire Irish squad for his abusive outburst, and faced his club manager yesterday to explain himself. He could be fined by the club, having previously been warned about his conduct on Twitter and Facebook.
He is also sweating on his place in the team to face Liverpool at the Stadium of Light tomorrow, with O'Neill's squad now containing greater flexibility after investments during the summer.
"He's been rather foolish and he has admitted it himself," O'Neill said. "He has taken himself off Twitter, he could have a situation with Facebook as well, and 14 other accounts. We will have to rectify it.
"We can have a joke about it, a laugh about it and think that that is OK, but he knows the rules and they were read to him. He was there that day. Some of his language is pretty poor and we will genuinely have to deal with it. Now it is getting a bit ridiculous.
"I hate to use the word role models because some players can do great things outside a football club and it never gets recognised. These players here at Sunderland do as much outside work as any players I know at a football club, but in this situation James has to learn to temper everything and really rein it in. He has to show some responsibility.
"James has been acting kind of strangely. It's good when a player wants to play and also wants to manage the team. He is rather young for that at the moment, and Mr Trapattoni has a couple of years and a couple of titles on him.
"James has got to learn. It's his choice of language, he can't be swearing on these things [social websites], he should have a wee bit more sense. He has to abide by the set of rules we have here, and if he is not playing on Saturday then you will realise."
McClean was bought by the former Sunderland manager Steve Bruce in summer last year for a fee of £350,000, signing a three-year contract when he moved to the Premier League from Derry. He had to wait until O'Neill's arrival at the Stadium of Light for his career in England to burst into life, though, and he ended the campaign having started 29 games in all competitions, scoring six goals.
That caught the eye of Trapattoni, who persuaded McClean to play for the Republic, rather than Northern Ireland, for whom he had already picked up seven Under-21 caps.