Manchester United have already sought to improve their midfield options with the £24million signing of Ander Herrera, who has generated quite a following on the Red Devils' pre-season tour of the USA.

But following a season in which Michael Carrick, Marouane Fellaini, Tom Cleverley and Darren Fletcher found just two goals and one assist between them, few would dispute that Louis van Gaal requires further midfield recruits if he's to drastically change United's Premier League fortunes for the better.

Indeed, the Old Trafford outfit's engine room has required drastic modernising for some time, and with that in mind, here's a list of FIVE signings hat would completely transform the Red Devils in the middle of the park...

Angel di Maria

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FREDY GUARIN

Fredy Guarin

Manchester United's midfield still lacks that box-to-box presence, a genuine No.8 who can score goals at one end and put in an industrious shift at the other.

Thus, it's rather fortunate that Inter Milan have proposed a swap deal involving Fredy Guarin and disgruntled Red Devils striker Javier Hernandez:

The Colombia international measures in at 6 foot 2 and is famed for his physicality, but regularly contributes with goals and assists, as detailed below:

Fredy Guarin

And some of his strikes appear to defy all physical understanding. Here's a look at some of his best during spells with Inter, Porto and Saint Etienne:

//www.youtube.com/embed/QaLh1SmCXeg?rel=0

Most importantly, the 28 year-old offers mobility, energy and an added dimension going forward.

But it remains to be seen whether Louis van Gaal wants to part with a striker in Chicarito who has reached double figures in three of his four Premier League campaigns.

XAVI

Barcelona old-timer Xavi may be no spring chicken, but his quality on the ball remains undoubted and the Red Devils could certainly do with a central midfielder that dictates play.

Of course, the 34 year-old is regarded as one of the top playmakers in world football, having been at the heartbeat of a Barcelona side that's won three Champions League titles since 2005 and a Spain team that claimed two consecutive European Championships in addition to the 2010 World Cup.

Interestingly enough, he first emerged as a major player on the Nou Camp scene under Louis van Gaal, and could be in line for a Catalonia departure this summer despite rejecting moves to New York FC and several middle-east clubs.

Here's a look at what Xavi does best - destroying other teams with his world-class passing ability:

//www.youtube.com/embed/45G0egeyK20?rel=0

Manchester United could provide an interesting exit route for the Spain international, who was in decent enough form last season:

Xavi

But with investment in youth the flavour of the month at Old Trafford, LVG is likely to pursue younger targets first.

JUAN CUADRADO

Juan Cuadrado

Manchester United's flanks have been in desperate need of an injection of quality and pace for some time, and according to the tabloids, Fiorentina star Juan Cuadrado could be the man to provide it:

The 26 year-old absolutely destroyed Serie A last season and had a significant impact at Brazil 2014, as detailed below:

Cuadrado stats (2)

In fact, nobody at the tournament bettered his four assists:

world cup assists

Including this set-up to James Rodriguez:

Combining pace, athleticism, trickery and netting prowess, this goal typifies what the South American is all about:

//www.youtube.com/embed/DUlRxcSaxZo

But Manchester United are by no means Cuadrado's only suitors this summer - he's been on the radars of Barcelona and Bayern Munich for some time.

ANGEL DI MARIA

Angel di Maria

Another available winger that would significantly improve Manchester United's options out wide is Real Madrid's Angel Di Maria, who looks set to become the victim of James Rodriguez's £65million move to the Bernabeu.

It was believed the Argentina international was on the verge of joining PSG, but recent speculation suggests an Old Trafford switch could be back on:

The 25 year-old's World Cup was unfortunately cut short through injury, but he netted this vital last-minute winner against Switzerland in the round of 16:

And finished Brazil 2014 with the third-best dribbling return of any player at the tournament, as detailed below:

Di Maria dribbles

Domestically, a transition to a more central role saw Di Maria finish up as La Liga's top creator last season:

di maria assists

Here's a look at the South American's Top Ten strikes for Los Blancos:

//www.youtube.com/embed/ggIHrkMUsMk?rel=0

And United have recieved a transfer boost, following news that the Albiceleste star has grown disillusioned in the Spanish capital:

ARTURO VIDAL

With Kevin Strootman's injury ruling him out of a summer move, it appears Manchester United's transfer attentions are firmly set on Juventus star Arturo Vidal, with the Independent mooting a club-record bid:

The Chile international's box-to-box style, boasting robust athleticism, tackling ability and netting prowess, is seen as perfect for Louis van Gaal's attacking mentality.

Furthermore, the 27 year-old was in unbelievable form last season as the Old Lady and Vidal claimed their third consecutive Serie A title. Here's Vidal's vitals from the campaign:

Valbuena stats

And a look at his best moments from last term:

//www.youtube.com/embed/r8iKLIacxxw?rel=0

Sources are fairly unanimous in quoting the Red Devils' £48million offer, suggesting we could see some movement within the next few days.