MARTIN O'Neill has criticised James McClean's decision to reactivate his Twitter account, and warned the Sunderland winger not to do anything that could lead to disciplinary action.
O'Neill urged McClean to quit Twitter after the 23-year-old received death threats in the wake of his decision not to wear a shirt bearing the image of a commemorative poppy last November.
McClean, who has also been instructed by the Black Cats' media department not to use social networking sites, created controversy last September when he used Twitter to launch a foul-mouthed rant at Republic of Ireland boss Giovanni Trapattoni after he had been left on the bench for a World Cup qualifier in Kazakhstan.
The advice appeared to have got through, and McClean voluntarily left Twitter in early February. However, he posted two new messages this week, a move that has not gone down well with his manager.
"Is he maturing? No," said O'Neill. "No, he has gone back on Twitter - even against the advice of the club, he has gone back on. So he'll have to look out for himself then.
"I am learning about these things (social networking sites) all the time, and I have no major problem with people going on them. But what they don't seem to realise is whatever they say there goes into the public domain.
"As long as he doesn't start to talk about the football club, then fine. And as long as he doesn't swear. These are the things I would take exception to.
"There must be no derogatory comments about the football club, regardless. I am not so sure what we can do. I will have to have a look at it and see. But has he learned? We will see."
McClean will miss today's Premier League game with Arsenal after injuring his ankle during Ireland's midweek win over Poland.
The winger damaged his ankle in the first half yet was not replaced until the 82nd minute, something O'Neill concedes was not the fault of the Irish management.
"His ankle is particularly swollen, which is causing a particular concern," said the Sunderland boss. "I don't think he complained about the injury, so there's no blame attached. He played the 80 minutes, and it was only after he came off that the ankle started to really swell."
Carlos Cuellar is available after missing last weekend's defeat at Reading, but it remains to be seen whether the Spaniard is preferred to Titus Bramble.
Lee Cattermole remains a major doubt as his persistent knee injury continues to flare up. The skipper had been pencilled in for a return this afternoon, but O'Neill is expected to err on the side of caution after another setback at the start of the week.
"On Tuesday, he did the training and felt a bit of something," he said. "We've had another look at him and we could do with him for the last third of the season."