The Rossoneri�s reluctance to slow down the ageing process could be decisive for Celtic

At last week's Academy Awards, much was made of Helen Mirren's choice to grow old gracefully, eschewing surgery, botox and the other accoutrements of eternal youth favoured by so many of her colleagues. Mirren and AC Milan share not just a vague assonance, but also the refusal to go under the knife. The difference is that, while in Hollywood it may be a rare and noteworthy feat, in football it is not such a clever idea.

And so, 72 hours ahead of their match with Celtic, this Milan side find themselves close to the end of an era, both domestically and in Europe. Rather than regenerating themselves year on year, they have opted to grow old together, emphasising experience and cohesion over rejuvenation.

"I know that cycles of success begin and end," manager Carlo Ancelotti said recently. "We have adopted a certain strategy and it paid off for us we were in the semi-finals of the Champions' League just last year, remember? It's easy after the fact to go back and say we should have done this or we should have done that. I look at my team and I still see plenty of fight and vigour."

Yet the facts are there for all to see. Milan have 11 defenders on their books. Last Wednesday against Palermo seven of them were injured and one was suspended, forcing Ancelotti to play Christian Brocchi, a midfielder, at right-back. Giuseppe Favalli, who is 35 and had made just one league appearance since October, was drafted in at left-back. If you exclude the recently arrived Leandro Grimi (who has yet to make an appearance) and jack-of-all-trades Daniele Bonera, the average age of the other nine defenders is 37. No, that's not a typo: 37.

Of the likely starters in Milan's hypothetical Best XI (which we never get to see anyway, since somebody's always hurt), only three - Kaka, 24, Alberto Gilardino, 24, and Andrea Pirlo, 27 - are younger than 29. This is a club which has never renewed itself. Of the 22 players signed since the summer of 2004, Gilardino is the only one to have made a meaningful impact.

Milan have long been a benchmark of how a top European club ought to be run. They boast state-of-the-art training facilities, they spend more on their medical staff than any club in Europe and, thanks to an impressive commercial department, manage to break even year after year, despite having the second biggest wage bill in Europe. Under Ancelotti, they also play entertaining football, behave with a grace rarely seen in football these days and generally manage to garner the sympathy of neutrals (which, given their owner, Silvio Berlusconi, is positively loathed by half the country for political reasons, is quite a feat).

And yet you can't help but feel something has gone seriously wrong over the past 18 months. Events on the pitch only tell part of the story. Last year, they finished second, three points behind a disgraced Juventus, while coming within a dubiously-disallowed Andriy Shevchenko goal of taking Barcelona into extra-time in the semi-finals of the Champions League. This season, without the eight point penalty, they would be joint third.

But the malaise has manifested itself elsewhere. Shevchenko's departure was a big psychological blow, magnified by the fact that, instead of securing a big name replacement - Samuel Eto'o had been mentioned - they opted for the oft-injured Brazilian Ricardo Oliveira instead. His return of three goals in 20 Serie A appearances tells you all you need to know about his performance.

When they did bring in a big name, many saw it as a desperate gamble. Ronaldo, who is cup-tied against Celtic, arrived in January amidst much raising of eyebrows. The big man has done reasonably well, but you can't help feel he is one injury or one big night out away from falling prey to the troubles which marred his last year-and-a-half at the Bernabeu. And, at 30, he isn't getting any younger.

Meanwhile, there are signs of weariness up and down the squad. Alessandro Nesta, the club's best defender, has been in Miami since early December, recovering from yet another injury. The usually taciturn Nesta has announced he is homesick for his native Rome and would like to move back to Lazio, even if it means a big pay cut. Goalkeeper Dida's contract negotiations - his deal expires at the end of the season - stretch on endlessly.

But the real concern is Kaka, who is very much Milan's meal ticket at this stage. He was courted aggressively by Real Madrid last season and now Barcelona have stepped in. His most recent comments on his future have hardly steadied anyone's nerves. "Who knows what the future will bring?" he said last week. "Who knows where I'll be next season? It's in God's hands "

While it's true that Kaka, an evangelical Christian who sported a T-shirt reading "I belong to Jesus" when celebrating Brazil's 2002 World Cup victory, makes frequent reference to the man upstairs (no, not Berlusconi), it's equally true such statements do not bode well.

Milan's response, beyond the usual "He has a contract through 2011, etc", has been to drop hints Ronaldinho is the club's next big signing. They've even fantasised about an all-Brazilian frontline of Kaka, Ronaldinho and Ronaldo.

Leaving aside the obvious point it would leave Gilardino - who has been scoring regularly and at 24 represents the club's future up front - out in the cold, nobody truly believes that Milan can sign Ronaldinho without giving up Kaka to fund the deal.

Five years ago, when Berlusconi was bankrolling things Roman Abramovich-style it might have been a different story, but today, it would simply mean swapping a 24-year-old Brazilian superstar for one three years older. Even that is not guaranteed, given what Milan did the last time they sold one of their stars: Shevchenko was replaced by Oliveira, which led one commentator to joke if Kaka goes, he'll be replaced by Thomas Gravesen.

The Milan faithful look confused and battle-weary. Ronaldo is viewed with suspicion until he can prove himself. Clarence Seedorf has been booed of late, forcing Ancelotti to rise to his defence with words which aren't exactly reassuring: "Clarence is used to it, I don't think it affects his play." Milan's much-hyped physios and medical staff - the club love to go on about how its some kind of collective brain trust - are now a running joke given the amount of injuries they've had.

And even newly signed right-back Massimo Oddo, who is likely to start against Celtic and should be a genuine bright spot as he is arguably one of the best in the world at his position, is leaving a bad taste in people's mouths. In some ways, he epitomises how Milan lost their way.

Oddo is a product of Milan's youth academy, having joined the club at the age of eight. He never made a single first-team appearance, however, and instead was loaned out to five different clubs as a youngster, before being released at 24. He went on to become a star at Lazio, accumulating 25 caps for Italy and winning the World Cup in Germany last summer. Now, at 30, the club had to buy him back. Which, of course, is ironic, given that the Berlusconi era in Milan began with a gaggle of gifted homegrown kids: Filippo Galli, Demetrio Albertini, Billy Costacurta and Paolo Maldini.

Maldini and Costacurta are still there, of course, despite their combined age of 78. In fact, there is an outside chance Maldini could start against Celtic. And perhaps that's the heart of the problem. They are legends, much like Cafu, Pippo Inzaghi, Seedorf and others, but even legends need to know when it's time to go to bed. And, if they don't, they need a club who can politely lay out their pyjamas, fluff their pillows and usher them into the bedroom.

Not everyone can be like Helen Mirren. On Wednesday, we may find out that AC Milan are more like Rita Hayworth.