Manchester United's Defensive Challenges Under Michael Carrick
Michael Carrick knows the numbers. Five senior centre-backs, three full-backs who can tuck in, four competitions to navigate. On paper, Manchester United look stocked. In private, the manager is anything but relaxed.
Leny Yoro, Ayden Heaven, Harry Maguire, Matthijs De Ligt and Lisandro Martínez form the spine of a defence that could, in theory, carry United through the Premier League, FA Cup, Carabao Cup and a long-awaited return to the Champions League. The reality is more fragile. Carrick enters his first full season in charge with a backline that feels as likely to buckle as it is to blossom.
A manager stepping into the deep end
Last season was a controlled experiment. Carrick arrived in January, a steady hand after Ruben Amorim’s sacking, and inherited a team stripped of distraction. No cups, no Europe, just 17 league games to stabilise a listing ship.
He did that and more. United lost only twice – both 2-1, to Newcastle and Leeds – and conceded 18 goals in those 17 matches. Seventh place, 32 points on the board, nine behind Aston Villa in third, and a mood around Old Trafford that had shifted from mutiny to something closer to belief.
Now comes the real examination. A full campaign, four fronts, and a manager with only 20 games of United experience behind him. The question is no longer whether Carrick can calm a crisis. It is whether this squad, and especially this defence, can withstand the grind of a season that will not let up.
Promise and risk in equal measure
The romantic version of United’s backline is easy to sell: a blend of youth and nous, of high ceilings and hardened winners. Look closer and the picture blurs.
Yoro and Heaven are the great unknowns. Between them, they represent the future of United’s defence; right now, they are still raw materials.
Yoro, 20, already has 66 appearances since his £52m move from Lille in 2024. He has the tools: 6ft 3in, quick across the ground, composed on the ball. He has also shown, at times, exactly why young centre-backs are rarely trusted without a safety net. The mistakes have not been constant, but they have been costly enough to linger in the memory. United’s hope is that a third season in England turns potential into authority.
Heaven, 19, arrived from Arsenal for a nominal fee in February 2025 and quietly played his way into the conversation. Eleven league starts, flashes of his technique and speed, and a frame that suggests he will not be bullied. His own assessment is clear-eyed: he knows his age, knows his position, knows that managers rarely gamble on teenage centre-backs every weekend. For now, he waits, patient and ambitious, for the chance to turn promise into permanence.
The problem for Carrick is that he may not have the luxury of easing either of them in.
Maguire, Martínez and the weight of history
At the other end of the age spectrum stands Maguire, 33 now and carrying a career’s worth of scrutiny on his shoulders. He remains what he has long been: brave, committed, strong in the basics of defending, but one-paced. In a high line, against the best, that limitation can be ruthlessly exposed.
Yet Maguire offers something this dressing room still needs. He has captained United, lifted the Carabao Cup in 2024, and ridden out storms that would have broken others. He understands pressure. Under Carrick, he will expect to start the season as first choice, most likely alongside Martínez. On paper, that pairing gives United experience, aggression and leadership.
The catch is Martínez’s body. The 28-year-old, hailed by Pep Guardiola as “a top five centre-back in the world” after United’s 2-1 win over Manchester City in the 2025 FA Cup final, cannot stay on the pitch often enough. He left the World Cup final defeat by Spain before half-time with a muscle problem and remains a doubt for the opening league game at Hull. Every time he returns, he transforms United’s defensive edge. Every time he breaks down, Carrick is forced back to the drawing board.
Martínez is the kind of defender you build a system around. At present, he is the kind of defender you fear building a season around.
De Ligt and a back that will not cooperate
If Martínez’s fitness is a worry, De Ligt’s situation is a full-blown concern. The 26-year-old has not played since a 2-1 win at Crystal Palace on 30 November, his back injury finally requiring surgery in May.
By his own account, he pushed himself to the limit trying to avoid the operation, exhausting every avenue in an attempt to get back on the pitch. It did not work. Now the target is a return early in the season, and United cling to that timeline because they have to.
De Ligt arrives with the pedigree of a serial winner – league titles with Ajax, Juventus and Bayern Munich – and the aura of a defender who should anchor a backline for years. But until his back proves it can withstand the rhythm of English football, he is another question mark in a department that already has too many.
A defence built on hope, not certainty
Stack them up: Yoro, Heaven, Maguire, Martínez, De Ligt. On any given day, that group could look formidable. On too many days, it might not be available at all.
Carrick can turn to Noussair Mazraoui, Diogo Dalot or Luke Shaw as auxiliary centre-backs if the injury list bites, but that is a contingency plan, not a strategy. United’s defensive structure feels less like a carefully engineered unit and more like a puzzle that has to be solved anew every week.
All of this plays out against a transfer window that tells its own story about where United stand in the current arms race. Their rivals are not waiting around.
Manchester City have gone big on Eliott Anderson at £116m. Chelsea have pushed the boat out for Morgan Rogers at £117m. Tottenham have thrown down a marker with Sandro Tonali for £100m and Mateus Fernandes for £85m. These are statements as much as signings.
United, by contrast, have moved more cautiously. Youri Tielemans, 29, arrives from Aston Villa as the headline addition, a smart, experienced midfielder rather than a transformative marquee name. Andrey Santos, 22, joins from Chelsea with only 11 league starts to his name last season. Useful pieces, perhaps. But they do not answer the most obvious question about this squad.
There are still five weeks before the window shuts. The club can yet pivot, cash in on a defender, or pounce on an opportunity that reshapes the backline. For now, though, Carrick faces a season that will test every inch of his managerial nous with a defence built on caveats and optimism.
In a year when United return to the Champions League and attempt to close the gap on the domestic elite, that is a precarious place to start.
