You are often a better player when not playing, or so the saying goes. For Nicolas Jackson, it could hardly be more true.

Chelsea manager Enzo Maresca has been a big defender of the striker and last week the reason why became all the more clear. Even during the worst goalscoring run of Jackson's Premier League career to date he offers something that others at Chelsea don't.

His consistent and unrelenting running asks questions of opposition defences whereas Chelsea's other forwards are often happy to get the ball to feet, playing in the field of vision of the centre-backs, and opting to win a one-on-one battle, at best. For Maresca, Jackson is his tool to move the backline around, to create spaces for the other dynamic forces to operate, and then when he is on form, to score goals and provide.

It is notable that even when finishing has deserted him in the past two months, Jackson has two assists in his last four league games, both coming from areas that only Jackson causes danger. He remains a threat in a variety of ways and it is something that Chelsea are totally unable to replace.

Never was this more evident than the attempt to fill his vacant No.9 spot with Christopher Nkunku and Cole Palmer last Saturday away to Brighton. The performance on Friday night only exacerbated the same issues. In the days between meetings against Fabian Hurzeler's side, it was revealed that Jackson would be out until after the March international break.

It posed big questions for Maresca at a time whereby he didn't need them. Already challenged with managing a team out of form, out of confidence, and under the gaze of an expectant fanbase quickly losing faith if not in him and the squad then certainly those at the head of the club; being without a keystone and unique player is the last thing he wanted.

There is little room to hide for Chelsea, though. They played with fire in more ways than one, and now they have been well and truly burned. It cannot be said that the warning signs were not there.

For starters, Jackson arrived in England with just over 2,500 senior league minutes under his belt in Spain - and only 1,800 of those were in the top division. He played more than that in the Premier League alone last year and was on course to beat it this season.

That has posed multiple problems for Chelsea. Not only did Jackson come in as an inexperienced and raw option in need of protection so that he could continue to develop away from the pressures of football in this country, he has also had a physical toll put on his body.

Jackson has proven to be remarkably durable in his 18 months at Chelsea but has had to do the work of two players at times. Christopher Nkunku and Armando Broja hardly provided any support under Mauricio Pochettino and Marc Guiu has only really been a Conference League pick for Maresca.

Not only were Chelsea leaving themselves exposed by going without reasonable injury cover, it has potentially played a part in his muscles being stretched to the limit over an extended period. It is no surprise that he has looked mentally and physiologically fatigued in recent weeks.

This is still a 23-year-old who only started to play as a striker six months before Chelsea signed him for nearly £30million in 2023. Within three months, he was the sole option at No.9 due to Nkunku's unfortunate pre-season injury, and nothing has been done to remedy his position.

Jackson has had zero competition for his place, given no help in the tough times, and now there is nobody to take his place. It was a risk that Chelsea actively took, choosing not to bow down to Victor Osimhen's wage demands over the summer and remaining out of the mix in January too.

The timing of the injuries for Jackson and Marc Guiu - also out for the foreseeable future - are certainly unlucky, but the planning which left the squad exposed to such a scenario is not. Even with Guiu, Chelsea would be turning to a 19-year-old with plenty of energy and running power but no tangible evidence that he is ready to contribute at this level.

Those who have mocked Jackson may now be forced to re-evaluate him in the light of witnessing what a team looks like without him. Last week Chelsea were stale and devoid of physicality and energy, with nothing to build around up front.

Jackson offers all of those things even when he isn't at his best, and it was telling that Maresca went with an adapted mixture of Palmer up front against Brighton here. Nkunku was not far in his slipstream but it did not change his fortunes.

The Frenchman did start deeper than before, allowing Palmer to occupy the spot at the tip of the XI. For Nkunku, the withdrawn spot is a lot closer to the one in which he has excelled in throughout his career.

The decision might have paid off twice in the opening 20 minutes as Palmer received the ball in dangerous areas. Both of his efforts were wayward, though.

READ MORE: Gary Neville questions Enzo Maresca's Robert Sanchez decision amid 'big' Chelsea problem

READ MORE: Chelsea dealt huge injury blow as Enzo Maresca forced to make Brighton change

READ MORE: Man City Premier League legal battle decided as Arsenal and Chelsea given 115 charges verdict

When Brighton took the lead early it was indicative of a Chelsea side weak at both ends. Undone by a long ball from goalkeeper Bart Verbruggen, as well as Kaoru Mitoma's excellent first touch, it was against the run of play but all too predictable for a side without invention in attack and still shaky enough at the back.

The same was true after Yankuba Minteh's second. Chelsea had missed a big chance through Pedro Neto, also having a goal disallowed, before then conceding a scrappy one to rub salt in the wounds.

Even with the failure of last week's experiment there was a lack of alternatives for Maresca to turn to. He had admitted that it wasn't just Nkunku who he was considering as a possible replacement for Jackson but nothing of much use was on show.

A change back to Nkunku ahead came with the second half in an attempt to put Chelsea's best playmaker in his favoured pockets once more. It is now five league games without a goal for him and the annoyance was only too clear for him as well. In the 50th minute he sprinted through the middle during a counter attack he was not found with a safer pass being preferred. Palmer threw his head back and shouted into the sky in a moment of open angst.

Meanwhile, Nkunku offered little for his teammates to play off. He also offered near enough nothing in terms of unlocking a Brighton defence which wasn't truly tested.

The head coach has flip-flopped on his thoughts around Nkunku, stating he saw him alongside Jackson as a No.9 as one of his two players per attacking position on multiple occasions this season. That hasn't really been reflected by his actions. Largely it has been minutes off the bench replacing Chelsea's main striker rather than going alongside or behind him.

Now, Nkunku headed back to the south coast undercooked and still looking unnatural as the focal point of a team. Both he and Palmer were so false and the false nines in the FA Cup that Brighton may as well have been playing against 10 men at times.

Chelsea's reaction last week was seemingly to go into their shell and play for total control. With no runners to offer a threat in behind Brighton, the ball had to land perfectly to feet. The hosts were intelligent in their press and often won the ball back without too much effort, forcing Chelsea into a direct ball or via midfield regains that they were ready to pounce upon.

Maresca's setup for the league fixture was, therefore, under scrutiny. He has been criticised in recent weeks for being unable to respond tactically to changes in-game. Although he got a positive solution against West Ham it did not stop the talking, especially after such a toothless display at Brighton in the match to follow.

One of the ways he suggested could alter things was the use of wingers in a central role. "It could be a solution, for sure," he accepted. Noni [Madueke], Pedro [Neto] or even Tyrique [George], they can try and be a solution for us. Jadon [Sancho] with different kind of skills.

"When you don't have a proper nine, you probably need to use a different kind of nine but you probably have to change the way you want to play. You cannot be direct; you probably need more linking because you don't have a threat in behind. We will find a solution."

There was none of this on show. Instead of a free-flowing front line it was more of the same passive possession, missed shots when chances did occur, and confused play overall. Jackson himself might not have had much to go at if he was playing but it would have at least been something different.