For possibly the first time since August, Manchester United’s back-four should pick itself when Manchester City visit Old Trafford on Sunday afternoon.

The Reds’ defensive department has been hampered by injury and illness-related issues since the opening month of the season, meaning it has been impossible for manager Erik ten Hag to find a settled and consistent rearguard. Three of the four members that started the opening two games of the season are expected to miss Sunday’s derby, highlighting the sheer size of the problem.

Aaron Wan-Bissaka, Lisandro Martinez and Luke Shaw joined Raphael Varane in forming the back-four for United’s opening two Premier League outings this season, starting the win over Wolves and defeat by Tottenham Hotspur, but only the latter is currently fit. Shaw was the first casualty of that quartet, suffering a muscle injury in the build-up to the win over Nottingham Forest.

He’s the player they’ve missed the most for a collection of different reasons, though two have been more noticeable than others. The England defender was virtually an ever-present figure for Ten Hag last term, either at left-back or as a makeshift centre-back.

His United career, like those of several others, was resurrected last season, benefitting from Ten Hag’s elite-level coaching credentials. He made 47 appearances in total, scoring one goal and chipping in with six assists. He also made a significant contribution to the 28 clean sheets that were recorded in all competitions.

After initially losing his place to Tyrell Malacia after a shaky start to the Ten Hag era, Shaw wrestled his spot back after the former was given a schooling by Phil Foden in the 6-3 defeat to City last October. The former Southampton man has topped the pecking order at left-back ever since.

Though his statistics last season, both offensively and defensively, made good reading, Shaw’s game was about much more than just his work in both boxes. He was a key contributor to United’s style of play between both boxes.

Ten Hag, from the outset of his tenure, made it clear that he wanted to transform United into a possession-based team. The signings of Christian Eriksen, Casemiro and Martinez immediately highlighted in the summer of 2022, with the trio renowned for their ball-playing expertise.

Working in tandem, Martinez and Shaw almost immediately transformed the left side of United’s defence, with the duo’s ball-playing credentials shining through. Both are excellent at progressing the ball out from the back, and Shaw’s ability to do that in the left full-back position has been sorely missed in recent weeks.

Shaw, who turned 28 in July, was essential to United’s build-up play last season, progressing the ball forward and contributing to the transition. He also assisted with ball retention in midfield, sometimes tucking into the centre of the pitch, a trait which United have attempted to persist with this season.

Furthermore, Shaw is a first-class professional, who is never afraid to speak the truth. He fronted up after United’s dismal 2-0 defeat to Newcastle United in April, setting the record straight by telling several home truths. United need leaders of his ilk.

As well as that, perhaps even more crucially, his absence at left-back has been felt by Marcus Rashford. The United academy graduate, who scored the winner in last season’s all-Manchester affair at Old Trafford, has scored just one goal so far this season and has looked a shadow of the player he was last term.

Though he deserved tremendous levels of credit for what he achieved last season, becoming the first United player to score 30 goals in a season since Robin van Persie a decade earlier, a lot of his success was built on the fact he had sound knowledge he’d built a solid and fruitful partnership with Shaw. The England colleagues would often link up down the left-flank, displaying a firm understanding of each other’s personal game.

It was a reliable partnership, one which United frequently prospered from. Rashford has had anything but a settled partner on the left so far this term, with the left-back spot, in Shaw’s absence, having been shared between Sergio Reguilon, Victor Lindelof and Sofyan Amrabat because of further injury troubles.

The sooner Shaw overcomes his muscle problem and returns to full fitness, the better, both for United as a collective and Rashford personally. He is a vitally important cog in the way Ten Hag wants his team to play, and his presence has been sorely missed.