Roy risks ending up an outcast

The reaction is unlikely to be as it was among his Republic of Ireland colleagues during the summer. They decided enough was enough after Keane went into print and criticised their preparation for the World Cup and so backed Mick McCarthy in his very public dispute with the team captain.

At United the deep sense of professionalism and pride will probably leave the players reluctantly nodding in agreement with the Irishman, even if they feel it was something that could have been said behind closed doors and not in a book now being serialised by two national newspapers.

Add to that Ferguson's admiration for Keane and the 31-year-old would appear to be on fairly safe ground.

Keane does have a reputation for speaking his mind, even if the complex nature of his personality means his words can be delivered in a variety of ways. At times charming, articulate and far more intelligent than many give him credit for, he can just as easily let off steam with a volley of fourletter expletives.

News that he decided to walk away from United after his dismissal at Newcastle last season comes as no great surprise. In the end, Keane refused to play in this year's World Cup on a point of principle and the chances are there will be other such moments before he finally retires.

One of Keane's greatest qualities is just how seriously he takes his football. If everything is not to his satisfaction it seems he would rather be at home walking the dog. When, in his own mind, he called into question his worth to the team - his altercation with Alan Shearer that afternoon left him beginning to think he had become a liability - he decided to quit.

In his book he expresses relief that Ferguson persuaded him to stay, just as he does Ferguson's decision earlier this year to remain as manager for three more seasons.

When Ferguson announced he would retire at the end of last season he said it was because his devotion to the cause had come at a cost. In giving so much, others - namely his immediate family - had suffered.

Keane feels similarly committed and it is perhaps because of that single-minded determination to succeed that he and Ferguson prove so intolerant of those who fail to match their ambition.

There is a darker side to Keane that still causes concern and not just for his lawyers after he admitted that his vicious tackle on Manchester City's Alf Inge Haaland in May 2001 was entirely premeditated. That might be one that also makes the Football Association sit up and take note.

Keane is the first to admit he occasionally struggles to control his competitive instincts and, in a sense, he should be admired for his honesty. But as Jaap Stam discovered, revealing all can sometimes leave one rather exposed.