Manchester United have been linked with Borussia Dortmund's Mats Hummels for so long there's now enough tabloid reports on the saga to write a 300 page novel.

Not a particularly exciting one mind you. The majority of the chapters would be titled either 'Man United to bid for Hummels' or "Hummels contemplates Old Trafford move'.

Indeed, the press have exhausted every word in the dictionary twice-over whilst attempting to keep us updated on all things Hummels-to-United related, to such an extent you might be forgiven for thinking the long-anticipated move to Carrington will never happen at all - especially after the 26 year-old's promotion to Dortmund captain at the start of the season.

But now ending a campaign in which the Black-Yellows have spent most of their time flirting with relegation from the Bundesliga, all-but-mathematically confirming they won't be in next year's Champions League tournament, if Hummels is to ever leave the Black-Yellows, it will almost certainly be this summer.

So with that in mind and Louis van Gaal's interest in the domineering centre-half well known, here's FIVE reasons the Red Devils must sign the Dortmund star in the coming transfer window.

HE CLEARLY WANTS TO MOVE TO UNITED

Whilst most tabloid rumours regarding Manchester United targets remain ever-shrouded in speculation, Mats Hummels has made it incredibly obvious that he's interested in a move to Old Trafford this summer.

This week, we've not only received news that the Germany international is undecided on his Borussia Dortmund future, but furthermore that he once promised Sir Alex Ferguson that if he'd ever move abroad, it would indeed be to Manchester United.

Price-tag remains another issue, but the 26 year-old's interest in a Red Devils switch this summer is patently obvious.

UNITED NEED SOMEONE WHO CAN PLAY OUT OF DEFENCE

Phil Jones' lack of technical quality was evident enough during England's 1-1 draw with Italy on Tuesday night, as the centre-back struggled to find any sort of rhythm or range as the Three Lions' deepest lying midfielder.

Chris Smalling isn't particularly snazzy with his feet either - in fact, quite the opposite - and the same can be said for Johnny Evans, which is one of the reasons Louis van Gaal's 3-5-2 system never quite paid off. The centre-backs would shuffle the ball aimlessly between themselves, lacking the quality and vision to get it forward.

Hummels, on the other hand, is famed for his Franz-Beckenbauer-eqsue, ball-playing qualities. The 26 year-old often instigates or joins attacks from deep positions, last term averaging an impressive 1.22 successful dribbles and 0.6 chances created per match.

His ability to drive from defence will bring a whole new element to United's build-up play - and potentially give LVG's 3-5-2 a new lease of life.

A STATEMENT OF INTENT

Nobody doubts Manchester United's ambitions to become the Premier League powerhouse of yesteryear once again, but signing Mats Hummels this summer would constitute an enormous statement of intent on that front.

Big signings, such as the Germany international, can often bring a lift to the whole club, galvanising the fans and commanding a higher level of performance from the rest of the squad.

Although the Dortmund star may come with a rather sizable price-tag, it'll be worth every penny if 'the Hummels effect' quickly leads the Red Devils to their Premier League first title since Sir Alex Ferguson's retirement.

HE'S A DEFENSIVE LEADER

In my opinion, what Manchester United lack most is a defensive leader - a commanding yet calm presence amongst their back six.

Michael Carrick is well experienced but has never been the most convicted of characters, whilst Phil Jones, although infectious in his enthusiasm, is still only 23 years of age and some way from maturing into a flawless, all-anticipating centre-half.

In contrast, Hummels has played in World Cup and Champions League finals and served as Dortmund skipper for the last season.

His quality, experience and leadership would not only improve United's backline, but their ability to defend as a well-organised, cohesive unit.

MANCHESTER UNITED WON'T DO BETTER

Despite all of the aforementioned points, this isn't simply a case of Hummels particularly suiting the Red Devils (although he unquestionably does).

The fact of the matter is that United need another centre-half and he's easily amongst the best in world football.

That combination of aerial dominance, technical flair and committed defending has seen the 26 year-old claim back-to-back Bundesliga titles with Dortmund, a World Cup title with Germany last summer, consecutive spots in the illustrious ESM Team of the Year for 2011 and 2012 and a place in FIFA's 2014 Dream Team.

There aren't too many in Hummels' class at the minute. Perhaps the likes of Real Madrid's Sergio Ramos, PSG talisman Thiago Silva or Giorgio Chiellini of Juventus, but none are particularly likely to leave their respective clubs any time soon.

In comparison, Hummels is almost certainly ready to try a new challenge next season.