Roy Keane, the controversial Ireland and Manchester United midfielder, was yesterday said to be still coming to terms with the news that he will not play again until next season. Earlier, the worst had come to the worst for the Irishman when exploratory surgery revealed that he had in fact, sustained one of the most dreaded of all football injuries and severed a cruciate ligament after an attempted tackle on the Leeds United player, Alf Inge Haaland at Elland Road last Saturday.

He is expected to undergo an operation to repair the ligament once the extensive swelling on his knee subsides. Not until the damage has been fully assessed, will it be possible to nominate a date for his return to the game but it is generally accepted that his involvement in the current season is now over.

From a Manchester United viewpoint, it will raise new doubts about their ability to retain the Premiership title and, more critically, their hopes of building on the promise of early wins over Kosice and Juventus in the European Champions League.

The bigger concern by far, for Irish enthusiasts is how his absence will affect the national team's prospects of surviving the World Cup play-offs and, in the longer term, their ability to stay competitive if they reach the finals in France next summer.

"It scarcely needs me to say that he's a huge loss," said Mick McCarthy. "He was enjoying his best season yet in international football and was outstanding in each of our last two games in Iceland and Lithuania.

"His kind of talent is irreplaceable and to that extent, it's a serious setback. But the reaction of the other players in the squad, will be to re-double their commitment to keep the momentum going until he is fit to return.

"Great as the blow is to Manchester United and Ireland, the biggest loser by far, is Roy himself. He now finds himself out of football at a time when he had so much to give and that's a shame."

Thanks to medical science, the injury which once ended careers is now treatable. But the timescale and, ultimately, the extent of the recovery, varies from individual to individual.

Manchester United backroom staff were yesterday making comparisons between Keane and Alan Shearer, another high profile player currently rebuilding his knee. Shearer's progress has been described as exceptional, a fact attributed to his renowned physical and psychological strength.

Keane is likely to prove no less resolute in this, quite the biggest crisis of a brilliant career and after starting his rehabilitation in the gym, could be back in light training by March.

Among those whose advice Keane is likely to seek is Niall Quinn, his Republic of Ireland team-mate who had the misfortune to tear the cruciate ligament in both his knees, on separate occasions.

In the first instance, he was back in full training in just over five months and with the benefit of experience, was marginally faster the second time after damaging his knee in a game for Sunderland exactly a year ago.

Theoretically, Keane could be fully fit again before the end of the current season and, in the event of Ireland reaching the World Cup finals, available for selection. The reality is however, that any such move, would be thwarted by Manchester United.

Quinn's experience was that even though he received a medical clearance to start playing again in time for the 1994 World Cup finals in the United States, he was effectively denied that opportunity at the insistence of Manchester City officials. There is nothing to suggest that the other Manchester club will be any more sympathetic to Keane's professional instincts if he gets himself fit again before next summer.

Either way, the timing of this mini tragedy is cruel for it comes at the prime of his career at a time when he is giving real substance to Alex Ferguson's long held view that he is, indeed, the most effective midfield player in Europe.

In the meantime, Ferguson has no immediate plans to buy a replacement. "I shall not be rushing out to sign anybody for the very good reason that there are very few players around capable of taking Roy's place," he said.

"The injury is a bad one but Roy is okay now. The technology for dealing with this kind of injury is a lot more advanced than it was even three or four years ago. He'll be back as good as ever, of that I've no doubt."