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Manchester United supporters were left bemoaning the club's lack of activity during the January transfer window given the perceived need for additions to the club's defensive line; however, with Louis van Gaal's side sitting in third place, the quiet January may not turn out to be the disaster many expect.

As ESPN FC's Miguel Delaney points out, the club approached the end of the transfer window with only prime targets in mind. There would be no stopgap defensive signing and in truth nor should there have been.

Van Gaal's main targets are believed to have been Kevin Strootman, Mats Hummels and Nathaniel Clyne, with all three players being identified as long-term solutions to problematic areas of the first-team squad. Despite the club testing the waters with regards to all three players over the course of the January window, none of the three deals came close.

There was significant speculation surrounding Aleksandar Dragovic and Nicolas Otamendi, as reported by Pete O'Rourke of ESPN FC and the Manchester Evening News' David Lynch, respectively. However, Manchester United quashed both those rumours in swift fashion.

While both defenders have impressive qualities of their own, I think it would be fair to say neither could be placed in the world-class bracket, with perhaps Otamendi just on the cusp following an excellent start to life in Spain with Valencia.

The key term there is "world-class," this is what Manchester United need in their defensive line. There needs to be a defensive leader who can help others through matches. If we look back to United's difficulties at the back earlier in the season, with goalkeeper David De Gea the only reason why United didn't drop more points at that time, it was because of a lack of leadership and calm within United's defensive ranks.

Marcos Rojo has settled into life at Old Trafford excellently, with the Argentinian becoming United's most reliable defender, although there are still questions about his inability to avoid being caught out by the aerial ball at least once per match. Rojo is the rugged, focused defender you need in a back four, yet he still needs a composed figure of stature next to him.

Chris Smalling is probably the best defender United have in terms of bringing the ball out from the back and not panicking when in possession, but he doesn't slot into the world-class bracket, or even come close. Mats Hummels does, and the prospect of a Hummels and Rojo partnership next season, with United almost certain to go back in for the German international in June, is an exciting one.

The likes of Phil Jones and Jonny Evans have been unlucky. You simply don't become bad footballers overnight, yet the impacts of injuries and lack of consistent playing time have hampered both of their respective developments.

Being part of the Manchester United team that fell from grace with such a remarkable thud last season was not easy for any player.

Playing under Sir Alex Ferguson alleviated pressure on players to a degree. There was still mammoth pressure, but players were never scared of playing or completely bereft of confidence. The 2013-14 season knocked the confidence right out of United's squad with Jones and Evans being two who were hit particularly hard.

It would be fair to say both players may not be at the required level to be first-choice for Manchester United, but both have their merits as defenders when playing with confidence. Let's not forget it was only in April 2013 when Sir Alex Ferguson stated that Jones was on course to be one of United's greatest-ever players, per Simon Stone of the Press Association via Daily Mail:

Jones is going to be a phenomenal player. He has a fantastic influence, no matter where he plays. He has an instinct for the game and a drive about him. I have no idea where his best position is. He could play anywhere on the pitch. But he will be one of the best players we have ever had.

If Dragovic had been brought in as a stopgap option for six months until Hummels was available, it may well have had a slightly positive impact on United's defensive resolve; however, that was not a guarantee with a player relatively untested at the highest level.

There then becomes the question of what to do with him when further defensive reinforcements arrive.

United's squad was allowed to bloat over the past seasons, with a number of players not of the required quality to start regularly for a team of United's standard, these players were believed to be on sizable salaries and difficult to offload when Van Gaal took charge last summer.

United cannot afford a repeat of that situation, with the Dutchman now attempting to streamline the squad before making up to four key additions next summer to fully assemble a squad capable of challenging for major honours again.

A lot of United's performances have been below par this season, particularly since Christmas. However, it would be fair to say a lot of this is not down to the quality of United's players but relative to the difficulty of playing an unfamiliar system.

The lack of defensive quality and confidence put paid to the use of the 4-4-2 diamond in the early part of the season, although Van Gaal appears to be returning to that system in recent matches.

When United have a strong defensive core that Van Gaal has full confidence in, the hugely talented attacking players can be allowed to perform with the handbrake off, and only then will United be able to perform at the optimum level for this group of players on a consistent basis.

This season was always going to be one of difficulty, with the main goal irrespective of cup competitions being Champions League qualification. At present, United are on course to achieve that; they may have to put more faith in their defenders by using a system suited to attack, and Van Gaal appears to be doing that.

In an ideal world, the club would have been able to bring in an elite defender in January—one of Hummels, Raphael Varane or Aymeric Laporte—but it simply wasn't possible.

This is by no means a disaster, with the club having more than enough firepower to secure a top-four finish, the challenge now is building confidence in United's current defensive line, finding some consistency in attack and then blending the two together.

This will take time, but if successful, United will have more than enough to qualify for the Champions League again and then turn attentions to restructuring the defence in the best possible manner, rather than rushing into a short-term fix.