Rio plays the unflappable leader elect

Considering that he was some miles away, limbs rendered inactive by surgery, mind still dulled by anaesthetic, it says much about the Manchester United captain that his name still permeated proceedings on Tuesday night. Keane-less and hence dis-United was the tone of most dispatches, and it is true that Sir Alex Ferguson's remnants were not at their pulsating, bewitching, pre-eminent best.

Even when the Old Trafford totem is present, it must be added, United have at times been just as desultory – typically when they confront a tactically astute, highly organised team like Steve McClaren's Middlesbrough. But here, according to the Keane aficionados among the prawn-eaters, the season-ticket holders and the commentators, United were not just a captain short, but a Superman light of a complete Marvel Comic parade of heroes. They mourned the non-availability of a character who is both mythologised and demonised, almost as if he had passed on, not merely gone under the knife in order to have some repair work carried out on a hip.

Keane is a crucial component of United's success in the opinion of those who insist there is a direct correlation between the Irishman's presence and United's level of performance. No one disputes the fact that he is a sublime director of tempo, hugely energetic and a demanding leader. Few coaches would not avail themselves of his presence given the opportunity. But indispensable?

Not all judges would say so. As George Best wrote in his recent autobiography: "Watching United's match against Arsenal at the end of the season, Roy did nothing. He was the one who didn't have a good game. And I hate to point out that when Man U did win the Treble, Roy was not in the team."

Still, it is argued, without him the fires burn less brightly, an inference that the likes of David Beckham and Ryan Giggs, Paul Scholes and Nicky Butt, Ruud van Nistelrooy and Rio Ferdinand may live with for the sake of harmony, although one that is hardly liable to engender an attitude of comradeship.

Best added: "The way he had a go at his Manchester United team-mates towards the end of last season, saying publicly that they weren't trying, was plain silly. All players at that level give it their all, and what he said was just insulting and something that doesn't foster team spirit." Neither, Best might have written after last Saturday, was shoving Phil Neville for a foolish challenge. Indeed, from Ferguson's perspective, that may be regarded as a greater sin than elbowing Jason McAteer. Both diminish a player regarded by many as the most complete in Europe, and render him instead a liability.

The hiatus in Keane's season may be welcome. Condemned by the public, bitten by squirming snakes of the media, he has become the subject of his very own game show: I'm the captain of Manchester United – get me out of here.

That is why, although Ferguson will be troubled by Keane's absence, he will, you suspect, regard the prospect of his return with even more trepidation. Ultimate defender of the Keane faith the Scot,who was constructed from similar DNA, may be, but he will scarcely have been blind to the disturbing signs within his team.

Maybe, just maybe, all will revert to normal when the Irishman re-enters the fray. Unlikely. The fear of Ferguson will be that Keane's feuds with certain Irish players, his criticisms of his own club team-mates and his reaction to the Football Association's charge of bringing the game into disrepute will all conspire to diminish his prowess on the field.

Ferguson will recognise that, albeit only privately. Those who suggest that Keane will deal with it all because he is "mentally strong" had only to view the evidence at the Stadium of Light last Saturday. His vendetta against McAteer suggested precisely the opposite.

Ironically enough, it is the player himself who contends, with a degree of contempt, that "instability eats away at the fabric" of Manchester United's rivals, including Arsenal. Ironic, because he makes the observation in the autobiography that has contributed in great measure to his current problems, including even uncertainty over his future.

Creating stability has always been Ferguson's forte, but suddenly he is faced with the dilemma of a player whose presence has become too great for a club even with United's capacity to accommodate egos. Only time will reveal if Keane can reassert himself as United's greatest influence, but one cleansed of the more demonic instincts.

Ferguson, however, did not progress to his stature today by not anticipating every eventuality. In lavishing a knight's ransom on Ferdinand, he knew he was not merely acquiring an exceptional defender. On Tuesday, the United manager cannot have overlooked the qualities of a player who, through United's shortcomings, radiated authority in an exhibition of strength, both physical and cerebral. Like the late Bobby Moore, with whom the former West Ham man is frequently yet rather unjustly compared, his reading of the game and timing of challenges are exemplary, yet he displayed against Boro that he is also robust and resourceful enough to handle any forward. The imperious style with which he muscled Massimo Maccarone off the ball was a delight.

For the present, Giggs and Beckham are entrusted with the captaincy, a responsibility which habitually has been crucial at Old Trafford, although Ferguson's field marshals, including Robson, Cantona and Keane, have all had their idiosyncrasies.

But if ever there was a player who merits the captain's armband and who represents the talented yet imperturbable future of United it is the £29m man who came of age during the World Cup.

On Saturday, the 23-year-old Ferdinand will be welcomed back to Elland Road. Well, perhaps that's expecting too much during a Leeds-Manchester United contest, but it says much about the respect he is afforded that he is unlikely to be subjected to the vitriol that Sol Campbell faced on his return to White Hart Lane.

His advocates would not pretend he was a paragon. In his younger years, Ferdinand was guilty of a drink-driving offence and made the pages of a Sunday tabloid following some unsavoury behaviour on holiday. But on the pitch, he may come to provide the face of rationality and moderation among those at Old Trafford who too often appear as gargoyles of dissent.