James Lawton: Late-vintage Keane will taste the sweeter on a journey which goes the full distance

There are plenty of precedents stretching back in a chain of defiant pride

Roy Keane might have felt very much alone when he considered what was left of his football world after Manchester United escorted him to the door, as he shed what were lightly described as tears of rage, but by the end of this week you could you see that he felt about as isolated as a movie star leaving his print on Hollywood Boulevard.

The embrace of Celtic Park was so warm Keane even made a kind of joke. Naturally, Keane being Keane, it leaned towards the sardonic, but there was a distinct twinkle in his eye when he said that he had always driven himself and his colleagues as hard as he could, and that up to a few weeks ago that had been OK.

Gordon Strachan, Keane's new manager, liked the aside better than most, as well he might. He knew rejection at Old Trafford when his own sand as a player was running down, and his reaction was as spirited as he believes Keane's will be in the green-and-white hoops. Strachan promptly won a championship medal with Leeds United, snatching it away from Manchester United, and he was still playing football of craft and significance at Coventry when he neared his 40th birthday.

No doubt Strachan made that point when the two met to cement a deal that will see Keane not as some ageing makeweight in the Real Madrid circus but the heart of a Celtic team certain to return him to the theatre of Champions' League football where he most distinguished himself. Another storming probability: Keane, closing on 35, Scotland's Footballer of the Year. The incumbent is big John Hartson. Do not expect fancy odds if you back Keane for next year's honour.

If all this sounds fanciful, it should not; at least not when you have skipped through a few precedents, and also considered the fact that Keane's last injury was something that can come to a player at any age in any circumstances, a broken bone in the foot during the ferociously fought 0-0 draw with Liverpool at Anfield earlier this season. While widely assigned to the company of football's ageing halt and lame, Keane was in fact the outstanding player in that match of attrition. Steven Gerrard scarcely got a kick.

Now for the precedents. They stretch back in an unbroken chain of defiant pride and ambition. Francis Lee, the hero of Maine Road when Manchester City were arguably the most exciting team in England, was reluctant to move down the road to Derby, but he finally said yes and was rewarded with another championship medal. At the old Baseball Ground they had seen such a thing before. Raich Carter was heartbroken when he went there from his beloved Sunderland, but he promptly found glory in a Wembley Cup final victory.

In fact, Derby was a field of re-awakened dreams for ageing master footballers. When Dave Mackay was given a sweetheart parting deal by a grateful Tottenham Hotspur, while rivals Manchester United were demanding from Middlesbrough £25,000 for a Nobby Stiles who had cost them nothing as a boy 14 years earlier and whose knees were now shot, the idea was that he would go away to graze in some quiet pasture like a champion racehorse. Instead, he was part of the foundation of Brian Clough's brilliant managerial career, driving Derby out of the Second Division and into a high place in the top flight.

Don Revie's Leeds United invited the ferocious Bobby Collins to reinvent himself once again after brilliant stints at Celtic and Everton, and his reward was competitive standards which would pass any scrutiny, including Keane's. Collins was voted England's Footballer of the Year several seasons after Everton had decided he was nudging into his football dotage. Collins came back from a broken leg and all the assaults of the years, and he was still playing Sunday football in his mid-sixties.

Tony Book was late in his thirties when, after superb years at Manchester City, he was voted Footballer of the Year - a prize he shared with Mackay. Such spirit does not dwindle because of some arbitrary decision that you are past it.

John Giles, Collins' successor as the general and the enforcer of Leeds' ambition, still felt he had something to give on the field when, at Keane's age today, he was sold to Second Division West Bromwich in the summer after he had played in a European Cup final against Bayern Munich, one in which scabrous refereeing helped the Germans to a fortunate victory. Giles buried his angst and, as player-manager, guided Albion to promotion, then seventh place in the First Division. "They were two great years for me," he says now, "and I can envisage Keane similarly enjoying himself. You reach a point when every game is a bonus, and it is wonderful when you discover that you can still do it."

You do not have to scrabble around for reasons why Keane should feel a surge of new life this weekend. Lee, Mackay, Collins and Giles were just the tip of an indefatigable iceberg. Stanley Matthews was supposed to be a relic, at 48 years of age, when Tony Waddington took him to Stoke City. But Matthews, plainly, could still play in astonishing, staccato fashion, and he filled the Victoria Ground. That was Waddington's stock in trade, a flair for recognising the summer wine that still had some bouquet. Dennis Viollet, Jimmy McIlroy, Peter Dobing, and Jackie Mudie were others who came to Stoke still with some strength and fine flavour in their games. Lawrie McMenemy unashamedly borrowed the Waddington trick when he drew on the experience and the desire of veterans like Kevin Keegan and Joe Jordan.

Jordan went to Southampton after Leeds United, Manchester United, Milan and Verona, and of course he scored goals. Many years later Jordan reflected, "When Milan decided they weren't going to keep me, Lawrie felt that I fitted in with his liking for players of experience and proven track records - but first I had to deal with the reality that the future had been taken out of my hands. It shook the old certainties and was a reminder that in football your fate is ultimately always dependent on somebody else's opinion and the need to avoid serious injury. For the great clubs a footballer has his time and then he is gone like an old brown leaf in autumn."

In Glasgow this week Keane asserted that he would not just shrivel away, and you can be sure hundreds of old footballers, nursing their aches and their arthritis without too much regret, gloried in his declaration, especially the remark, "People seem to think I'm 94 - not 34". It is one of the many cruelties of the game that such assumptions are made so easily. Pat Jennings, the great goalkeeper of Tottenham, was suddenly deemed to have reached a point of decline. So he moved, with beautiful irony, to Highbury, where he performed with such brilliance and nerve his appearances at White Hart Lane were guaranteed moments of the deepest of embarrassment among the Spurs' directors.

In the case of Manchester United that risk is restricted to the Champions' League draw, but be sure it will lie there like an unexploded bomb.

Keane's only obligation now is to be true to the best values he brought to his career; not the stridency, or an ambition that sometimes was hard to distinguish from pure, bullying thuggery, but that endless demand on himself to produce the best he could on behalf of his team. That is the glory in which Celtic have invested.

It is gilt-edged speculation because there is a clear linkage in all the names that we can associate now with Keane's determination to draw something of value and genuine achievement from the last of his years in football. Consider those names: Lee, Mackay, Collins, Giles, Matthews, Book, Keegan, Jordan, Viollet, Mudie, McIlroy. All of them were players who went the distance, who called on all of their talent. All of them finished as they started, playing to their limits, refusing to go a moment before their time.

It is something you cannot call up when circumstances require. It is not about spinning out the days in the sun, picking up another pay cheque. It is something in your bones.