Injuries to Vidic and Ferdinand could cost Manchester United the double

If any more proof were needed, this season has confirmed just how crucial a large, talented squad is for success in the modern game.

Arsenal FC have fallen away in recent weeks because their relatively thin squad was shorn of Eduardo, a fully fit Robin Van Persie and Tomas Rosicky. And despite all their off-Field problems this year, Chelsea have launched a title challenge on the back of having a squad full of experience and great depth.

The Champions League has also confirmed the importance of a strong bench, showing that many of the Italian and Spanish teams do not have the squad depth of the English sides. The exception to this rule is Barcelona who boast probably the finest squad outside of the Premier League.

The reason squad depth is so crucial is being shown clearly at Manchester United now. After their win over Aston Villa it looked unlikely that United could be stopped. Whilst they still hold a commanding lead in the Premier League and an almost definite place in the Champions League semi-finals, a potential spanner has been thrown into Alex Ferguson’s plans.

Injury to Nemanja Vidic was brushed aside in the 2-0 win at Roma. Rio Ferdinand was immense in the Stadio de Olympico and in all truth the second best team in Serie A appeared to be scared of a side that had thumped them so convincingly last season.

However, at Middlesbrough on Sunday the defence sorely missed Vidic. John O’Shea came in as his direct replacement and the back line was collectively unable to deal with Afonso Alves.

The worry for the United faithful is that in the next few games the United defence will face stiffer tests than Alves. With a home fixture coming up against Arsenal and a visit to Chelsea alongside a probable two-legged meeting with Barcelona, some of the best forwards in the world are likely to line up against the United defence. Didier Drogba, Emmanuel Adebayor , Samuel Eto’o and Thierry Henry will fancy their chances against a weakened United backline.

The defensive problems were exacerbated with the loss of Rio Ferdinand in the second half at the Riverside. These injuries have come around at the worst time of the season and have illustrated a surprising lack of depth in United’s defence. The use of Gerrard Pique underlined this yesterday.

Gary Neville’s long-term injury problems have forced Wes Brown to play at right back all season and although Brown has played for England this season he is not quite good enough, certainly not in comparison to the brilliant Patrice Evra.

But, in central defence it is quite amazing that the third and fourth choice centre-backs are Pique and O’Shea. Chelsea FC, for example could bring in Alex whilst Arsenal could draft in Phillipe Senderos, both of whom are better replacements than United can offer.

This is also bewildering when one analyses the depth in other positions at Old Trafford. For example, in central midfield Sir Alex can utilise (if all are fit) Paul Scholes, Anderson, Owen Hargreaves, Michael Carrick, Darren Fletcher and even Ryan Giggs for two, maybe three positions.

In the Sunday Telegraph Steven McClaren waxed lyrical over how “the most important lesson” the former England manager learnt under the tutelage of Alex Ferguson was “the season starts in the last 10 games”.

Football has a funny way of testing even the most prepared of managers and injuries to Vidic and Ferdinand could derail United’s double charge just as they affected last year’s European campaign.