Manchester United transfer window preview: Defence

Welcome to the first in a short series of posts previewing Manchester United's wants and needs in the January transfer market. With things fine on the goalkeeping front, we're skipping straight to the defence.

Louis van Gaal's tenure at Manchester United started underwhelmingly, and it's only becoming less whelming as time wears on. The Reds have painfully struggled for goals for a long time, with the Dutchman's tame tactics and inadequate personnel combining to leave United with little bark and even less bite. That considered, a win over Leicester City on the weekend would move United to the summit of the Premier League table for the first time since September: it seems we're still in the title race.

That is down to one thing and one thing alone: the defence. Van Gaal's United have been painful to watch with the ball at their feet, but as good as anyone in the league without possession. Their pressing is almost always excellently organised, and only in a freakishly bad performance against Arsenal (exacerbated by some woeful selection decisions from van Gaal) has it looked sub-standard. There's certainly more than just the defensive personnel to thank, with everyone across the field helping United to fight from the front. But that doesn't mean there isn't room for improvement at the back.

Centre-backs

Despite the massive improvement in Chris Smalling's level of performance, there are still question marks over United's defenders. Daley Blind started the season alongside Smalling at centre-back, but van Gaal soon realised that wasn't a long-term solution. Phil Jones has occasionally filled the role but a combination of his poor technique and incredible disposition to injury suggest Alex Ferguson was some way out when he crowned the former Blackburn Rovers man a legend in-waiting. Finally, Marcos Rojo looks a little more serviceable, but he seems to lack the trust of van Gaal to play anywhere other than at full-back.

That means that a new centre-back is one of United's top transfer priorities at the moment. The only issue is there seems to be a slight shortage. United are unlikely to ever pull off a move for Sergio Ramos; Mats Hummels will surely be targeted again in the summer, though there's no reason to believe he'll leave Borussia Dortmund at the drop of a hat; Marquinhos and Raphaël Varane are both at big clubs on big wages; and Aymeric Laporte, who van Gaal seems unlikely to gamble on anyway, may have already given Barcelona his word. If United get a chance to sign Marc Bartra at a cut-price fee, it might be as good as they're going to get.

Full-backs

For the opening few games, things looked spiffing at full-back. Matteo Darmian arrived from Torino for a more than reasonable fee, and started off as one of United's most impressive performers. Over on the other side, Luke Shaw hit the best form of his nascent Old Trafford career, adding genuine excitement to a team sorely lacking in it. What's more, the versatility of Marcos Rojo and Antonio Valencia meant there were a couple of players for each position, should they have been needed.

They were. And more.

Skip forward to November, and suddenly full-back is our defensive Achilles' heel. Darmian, whether chastened by van Gaal's instructions or suffering at the hands of the inexplicable force of poor form, has tailed off dramatically, and is now second-choice right back to Ashley Young. Which means that had Antonio Valencia not needed foot surgery, he may even be third-choice. For an Italian international, and a very good one at that, it's an alarming and bizarre state of affairs.

Meanwhile, over on the left, Shaw's season -- or at least a very significant chunk of it -- was cut cruelly short by a brutal tackle by PSV Eindhoven defender Héctor Moreno in September. A nasty break was the diagnosis, and a lengthy layoff the result. Rojo has been surprisingly impressive in Shaw's absence, though the Argentine undoubtedly lacks the technical dexterity of the man he's filling in for. It also means United are rather stretched in defence, and another injury or two could be very problematic.

That said, should United look to sign a full-back in January? Probably not. For now they're scraping by, and though it doesn't look too good at the minute, there's talent in the squad. At their best, Darmian and Shaw are perhaps the finest full-back pairing in the Premier League; the sooner they get back to form and fitness, the better.