Not Signing Daniele De Rossi Was Mourinho's Biggest Transfer Error This Summer

Chelsea are among this season’s favourites to lift the Premier League title for a reason.

Sure, they have the Jose Mourinho factor, but with or without their charismatic Portuguese boss, the Blues’ squad remains one to envy.

From the talents of Petr Cech in goal and John Terry at the heart of defence, along with Eden Hazard, Juan Mata and Fernando Torres in attack, Chelsea are an intimidating prospect.

They have strength all over, but there is one weakness—defensive midfield.

Chelsea’s 4-2-3-1 formation is designed to allow three attacking midfielders a degree of freedom further up the pitch and do the very thing that they have been selected to do—cause havoc, create goals and score them.

They have defensive duties of their own, but the two teammates sitting behind them in the pivot are very much an insurance policy, only Chelsea do not have any standout candidates to fill the void and make the position their own.

It’s why, if we’re being hyper critical of the Blues, not acting upon their rumored interest in Daniele De Rossi this summer was a major error in the club's recruitment policy.

Chelsea were linked with big names for even bigger transfer fees all summer. The most intriguing of them, however, was Roma’s Italian midfielder, who seemed the perfect fit.

When Kevin Strootman arrived in Rome from PSV Eindhoven in early July, The Mirror newspaper was convinced it would lead to De Rossi swapping the Olympic Stadium for Stamford Bridge.

And days later when De Rossie didn’t feature in Roma’s early preseason squads, the writing, it seemed, was on the wall, according to the Daily Mail.

A move never materialized, and while Chelsea have an array of attacking talent at the disposal, their frailties elsewhere cannot go unnoticed.

So far we've seen Frank Lampard and Ramires occupy the two deep-lying midfield positions this term. Chelsea haven’t lost any of their four matches—in regulation time at least—but it’s clear they have lacked the solid grounding a player of De Rossi's ilk would add.

Lampard, although 35 years old, still has that famed instinct for getting forward, while Ramires isn't known for being a defensive talent. New addition Marco van Ginkel may provide a solution, but outside of the Dutchman, the alternatives are few.

John Mikel Obi has never quite lived up to his billing, and Michael Essien's injury woes mean the Ghanian will never scale the heights he did during his early Blues career.

Mourinho knew of these shortcomings all summer, so it's a surprise that after van Ginkel and Andre Schurrle arrived early in the transfer window, Chelsea's next major signing would be another attacking midfielder, this time Willian.

He may not have been the glamorous addition that so many crave, but De Rossi has all the attributes to emulate what Claude Makelele did before him in West London.

De Rossi is relentless, physical and a major presence—something Chelsea will need in the big games this season. It's one thing passing their way through the likes of Hull City Tigers, but another altogether when their bigger rivals will throw down the gauntlet.

The Premier League will not be won or lost solely by the goals Chelsea score in 2013-14—those they concede will play just as big of a part.

With the transfer window now officially closed, the gaping hole in Chelsea's midfield seems bigger than ever, and Mourinho may rue not snapping up De Rossi when he had the chance.

Garry Hayes is Bleacher Report's lead Chelsea correspondent and will be following the club from a London base throughout the 2013-14 season. Follow him on Twitter here @garryhayes