According to reports from the ever-reliable and totally-not-sensationalist The Sun newspaper, Manchester United are targeting Tottenham defensive duo Kyle Walker and Danny Rose in a shock double-raid on their Premier League rivals.

It's claimed that Spurs would be incredibly reluctant to lose both in the same transfer window and Man United would likely have to shell out £30million-per-player - a rather substantial sum, even in the modern market, for a full-back.

Of course, we're taking this rumour with a pinch of salt and it seems any potential deal, double or singular, would take place at the end of the season rather than before the end of the current transfer window.

Nonetheless, there's no doubt the England internationals are amongst the best in the business when it comes to forward-thinking full-backs and would significantly add to United's starting XI.

In case you aren't quite convinced, we've got the statistics to prove the Red Devils should be putting a cool £60million on the table...

Mourinho unconvinced by current options

Feeling his way through an inflated Manchester United squad has been a constant theme of Jose Mourinho's first season at Old Trafford. We're now over halfway through and whether the Portuguese has cracked the perfect formula remains debatable, with David De Gea, Zlatan Ibrahimovic and the midfield three the only real constants over the last few months.

Even so, the sheer volume of players used at full-back this season really stands out. Whereas most Premier League clubs will have two options for either side and perhaps an emergency choice, Mourinho has already started nine different players in both positions this season - including winger Ashley Young.

Clearly, Mourinho isn't fully convinced by the options at his disposal - even Antonio Valencia's impressive form is by no means a guarantee for next season, with him due to turn 32 in August - and its hard to imagine United progressing much further under the Portuguese without indisputable choices on both defensive flanks.

Full-back one of the most important positions on the pitch

72 - The number of times PL clubs have started with three at the back this season

11- The number of clubs to have used it at least once in the PL

On the surface, this statistic may not seem particularly relevant to a club that has rarely experimented with three-man defences, a manager who has never veered away from a back four throughout a long, successful career and a transfer rumour that centres around two players who are full-backs first and foremost.

But scratch a little deeper, and this statistic highlights how important full-backs have become in the modern game, with a whopping eleven clubs ditching traditional attacking wingers to move their full-backs further up the field on at least one occasion this season.

No doubt, full-backs have evolved drastically since the 1990s. They were once asked to simply tuck in alongside the centre-backs, but full-backs these days contribute heavily at both ends of the pitch, requiring the box-to-box dynamism to do so.

As stated by Brent Maximim for Fusion.net...

"Elite fullbacks are expected to possess all the physicality of central defenders, the speed and trickery of wingers, and the stamina of box-to-box midfielders."

Jeremy Wilson holds a similar opinion...

" As [Jack] Charlton said, the full-backs are the only players on the field who regularly have space in front of them, and where there is space there is opportunity: if there is no direct opponent, there is the chance to overman."

In a nutshell, world-class full-backs are worth their weight in gold, capable of exploiting the space modern tactical thinking allows them. The Premier League has become so impressed by the increasingly attacking new breed of full-back that they're deploying systems previously deemed alien to the division in an effort to further capitalise on their abilities.

Although Mourinho may not necessarily belong to that school of thought, it's becoming clear full-backs are deciding games in the Premier League at an unprecedented rate. That's particularly true with Rose and Walker, which brings us nicely onto...

Rose & Walker are the best around

Few would dispute that Rose and Walker have emerged as amongst the best full-backs in Europe under the guidance of Mauricio Pochettino, but this set of statistics highlights how effective they truly are. Indeed, although they only come out on top in one instance (Rose for fouls won), throughout the continent's top five divisions, they rank in the top 21 left-backs and right-backs respectively on all five counts - epitomising their impressive all-round games and holistic contributions in both attack and defence.

Perhaps more intriguing is the relationship between the two when reading between the numbers. Indeed, Rose tends to rank highest where Walker ranks lowest and vice versa, so although they operate on opposing sides of the pitch, there's a real partnership that balances out individual strengths and weaknesses. Whilst even buying one would improve United's starting XI, snapping up the pair would have a much bigger, much more significant impact - justifying that combined £60million price-tag.