It may not be the most glamorous of positions, but right-back is still one that's long needed filling in Manchester United's starting XI.

Indeed, Ecuador international Antonio Valencia performed well as an emergency 'No.2' last season but is a winger by trade, whilst Rafael's Old Trafford career appears to have come to an abrupt end, with Louis van Gaal apparently offering out the Brazilian to potential suitors.

The only issue has been that some of the best right-backs on the market this summer have already reached conclusions over their respective futures. Southampton's Nathaniel Clyne is now a Liverpool player, Dani Alves signed a new contract at Barcelona and has since been joined by former Sevilla man Aleix Vidal, while Tottenham snapped up Burnley's Kieran Trippier for an incredibly reasonable £3.5million.

United are thought to have turned to Matteo Darmian of Torino, whose potential move is, reportedly, close to going through, but is he actually good enough?

Where could the Red Devils have turned instead? Well we at Football FanCast have been looking, and here are FOUR options they could have gone for...

MATHIEU DEBUCHY

The immediate fate of Mathieu Debuchy has been a regular talking point in the tabloids in recent weeks, with Arsene Wenger's side now well stocked at right-back thanks to the emergence of Hector Bellerin, who has been, arguably, better than the ex-Newcastle man.

But that shouldn't put Manchester United off the France international; his inaugural Gunners campaign was disrupted by a horrific ankle injury and the unexpected rise of the young Spaniard.

The 29 year-old is by no means the most spectacular of full-backs but he's well proven in the Premier League and offers a very consistent defensive game; averaging an impressive 2.5 tackles, 2.4 interceptions, 3.8 aerial duels and 5.2 clearances per match during his final season at Newcastle.

Whilst the 26-cap international may not have been a signing to take United significantly closer to the title, he'd have competently filled a gap in their squad.

Lukasz Piszczek

Lukasz Piszczek may have just endured a rather torrid campaign at Borussia Dortmund but it wasn't long ago he was widely viewed as one of the best right-backs in Europe, playing a leading role in the Black-Yellows' unexpected march to the 2013 Champions League final.

The Poland international is sturdy at the back - last term averaging 2.2 tackles and 1.8 interceptions per match - but better famed for his influence going forward, having begun his career as a right midfielder. That would sit particularly well with Louis van Gaal, who selected winger Valencia over defender Rafael for the vast majority of last season.

At 30 years of age, Piszczek probably wouldn't have been a long-term solution to the current lack of a resident No.2 at Old Trafford, but he's a proven defender with real ability.

GREGORY VAN DER WIEL

Manchester United have already been linked with Gregory van der Wiel by The Daily Mail, who claim PSG are offering out the Dutch international to Europe's top clubs.

Van der Wiel is a fantastic athlete with the pace and athleticism to contribute at both ends of the pitch for a full 90 minutes, which appears to be the model of full-back Louis van Gaal desires.

The 27 year-old is also well experienced, with 41 caps and 61 appearances in continental competitions under his belt, and knows the Old Trafford boss well from his successful spell as Oranje chief.

LVG would surely have been particularly pleased to have another Ajax academy product - who won the Ajax Talent of the Year award and the Dutch Young Player of the Year award during his Amsterdam Arena spell - in the Old Trafford ranks, too.

At The Daily Mail's valuation of £7million, he would have represented good value for money.

SEAMUS COLEMAN

The best option to have been aligned with Manchester United in my opinion; Seamus Coleman has established himself as the most prolific right-back in the Premier League over the last few seasons, claiming nine goals and four assists in his last 71 league appearances.

The Ireland international is famed for his mazy, powerful runs and long-range finishes - often drawing comparisons with Real Madrid's Gareth Bale - last season averaging 1.4 successful dribbles per match. Manchester United lacked that kind of penetration going forward for long periods of last season.

Coleman's proven in the Premier League, seems like a natural fit for Louis van Gaal's attacking philosophy and at 26 years of age still has plenty of football ahead of him.

Everton have been linked with Leeds United youngster Sam Byram as a potential replacement, but regardless, the tabloids believe the Toffees could still demand in excess of £15million for their goalscoring defender, so he would have been only a little more expensive than Darmian.