As Chelsea fans hoped heading into the campaign, Christopher Nkunku has had a huge hand in the Blues' fortunes so far this season - just not for the reasons anyone had wished.

12 months of anticipation culminated in the announcement of his £52m arrival from RB Leipzig during summer and Nkunku wasted little time entertaining supporters during pre-season. He featured in five games, scored three goals and appeared to be dragging everyone around him to higher heights.

Then he got injured.

Nkunku went down with a knee injury early in a draw with Borussia Dortmund and is not expected to return to the pitch until the very end of this calendar year or, perhaps more likely, the start of 2024.

The injury is obviously an enormous blow for Chelsea and one which has had a catastrophic impact on literally everything at Stamford Bridge.

What Nkunku brought to Chelsea during pre-season

Whether he was lining up as a central striker or as an attacking midfielder behind 'number nine' Nicolas Jackson, Nkunku was good. The Frenchman's love of exploiting space saw him float around effortlessly and provide a reliable focal point off of which Chelsea's forwards could bounce.

There were moments which proved Nkunku was still adjusting to life in his new side, but that's to be expected. What never disappeared, however, was the 25-year-old's ability to find a pass and score a goal - two things Chelsea have struggled with since he went down.

Nkunku appeared to be building a real rapport with fellow attacking recruit Jackson, who managed two goals and three assists in pre-season. While the France international wasn't involved in all of those moves, his impact on defenders and the confidence he inspires in those around him will undoubtedly have played a part.

Chelsea signed Nkunku because they wanted to make him a central piece to their puzzle, and for a few brief weeks, it looked like they had struck gold.

How Mauricio Pochettino has responded to Nkunku's injury

This is the real issue here. While Jackson was excellent in pre-season, he's clearly still too raw to be relied on to run the team's attack. Chelsea haven't got anybody to do that, with 28-year-old Raheem Sterling's purple patch at the start of this season lasting just two games before the experienced forward returned to his slump.

Nkunku was the only player worthy of trusting to provide a cutting edge, and in trying to find a solution, manager Mauricio Pochettino has abandoned everything positive about pre-season.

With justifiable concerns that Chelsea will no longer outscore their opponents, Pochettino is focusing on defence. The attack-minded Ben Chilwell has been replaced at left-back by Levi Colwill, who is a centre-back by trade and cannot be expected to bomb up and down the wing like Chilwell. He's there to try and stop Chelsea from conceding goals because Pochettino knows that, if the opposing side score once, they're probably going to win until somebody else steps up as a reliable orchestrator of Chelsea's attack.

That desperate search for movement and attacking intelligence saw Pochettino use Chilwell as a winger in the opening games, with the boss clearly - and rightly - believing the left-back's running makes him one of the team's biggest threats.

However, the problem there is that Chilwell is simply not an attacker. Any positive results of his tactical switch were only ever going to be short-lived and now, with the boss losing faith in his own experiment, Chilwell has been sent to the bench while Colwill remains at the back. Colwill is doing his job admirably, but it's not a job he should be doing in the first place.

Carney Chukwuemeka was asked to play in the Nkunku role early in the season and the 19-year-old threatened to give Chelsea fans a good time when he scored against West Ham United, only to pick up his own injury and send Pochettino back to the drawing board once again.

The keys were then given to Enzo Fernandez, who excelled in a deeper role in the season-opener against Liverpool before being shunted forward to the 10 spot in recent weeks. The Argentine is an excellent passer but currently lacks the movement and penalty box impact that elite teams need from their attacking midfielder.

It therefore came as no surprise to see Chelsea spend the final week of the transfer window searching for another forward who was a natural fit at the 10. The Blues ultimately took the risk on Cole Palmer, who has undoubtedly impressed in cameos but has left some fans nervous about the idea of putting al that trust in a 21-year-old who had just 489 minutes of Premier League experience to his name before his big money arrival.

Pochettino is searching for a solution but, while he still hasn't found one, is clearly aware that each passing week and the seemingly inevitable on-pitch disappointment that comes with it will see the pressure ramp up enormously. His focus now is on not losing games, rather than winning them.

What can Chelsea do to turn things around?

There was a moment late in Chelsea's 1-0 defeat to Aston Villa which should have provided Pochettino with some food for thought. Off the bench, Palmer weaved his way around a defender and unleashed a glorious over-the-top ball to the advancing Chilwell, whose deep runs from left-back are sensational and significantly more impactful than his uncomfortable darts forward as a winger.

It may not have led to a goal, but something happened. Chelsea looked good and dangerous as they created a situation which will inevitably lead to a goal if it happens more in future.

It's tough to ask Pochettino to have more faith in the attacking prowess of this group, but it feels as though that is the only way out of this. Rather than look for the next Nkunku, Pochettino must allow Chelsea's best players to play to their strengths and simply pray that the results come again.

The left-back role, and the elimination of Chilwell's attacking threat, is hurting Chelsea, who have also lost Fernandez's elite build-up play and ability to pick out runs from deep - the very runs he is failing to make when asked to play further forwards.

Football is an unforgiving game and Pochettino is well aware that, should a return to an attack-first approach fail to yield immediate results, it could cost him his job. It's an almighty risk to take but the reality is the only system that has been remotely successful since Pochettino arrived was his desire to play fluid, attacking football in pre-season.

Chelsea cannot continue like this, trudging around uncomfortably and checking Nkunku's medical chart in the hope he makes speedy progress. Something must change.

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This article was originally published on 90min as Christopher Nkunku's injury has derailed Chelsea's season - Mauricio Pochettino must be braver to fix things.