Let's rewind back to August 2023. Chelsea were taking on Borussia Dortmund in their fifth and final pre-season friendly of the club's tour of the United States.

Around two hours before the match was due to kick off, there were images released on X, formerly Twitter, of the pitch and the playing conditions at Soldier Field in Chicago. The whole of the Chelsea fan base became nervous and fearful. Just 10 days before the Blues' Premier League opener at home to Liverpool, there was no time for anyone to get injured.

Particularly not £52million summer signing Christopher Nkunku; who had featured in the four pre-season matches leading up to the Dortmund game. In those four games, the France international bagged three goals. Playing as almost a 'shadow striker' in Mauricio Pochettino's 4-2-3-1 formation, Nkunku produced some wonderful link-up with Nicolas Jackson, who was making an impression as a No.9 after signing from Villarreal.

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However, disaster struck for Chelsea. Rather - and frustratingly - predictably, the pitch took its toll. We will never know for certain that the conditions caused the injury but an estimated guess would suggest it definitely did not help in Nkunku's case.

The 27-year-old, then 25, was taken off after just 22 minutes of the game in Chicago. Pochettino spoke to reporters after the match and said how he was hoping the injury was not too serious - but it ended up seeing the former RB Leipzig attacker miss over four months of action, where he eventually made his debut for the Blues on December 19 in the Carabao Cup quarter-final victory over Newcastle United at Stamford Bridge.

Nkunku took, and scored, a penalty for Chelsea in the shootout on his competitive debut for the club. While supporters knew he was not going to be at his best straight away following a lengthy injury layoff, some could not contain their excitement.

Five days later, Nkunku made his Premier League debut in the Christmas Eve defeat away at Wolves. Coming off the bench with little over half an hour to play, Nkunku made his mark at Molineux with a header inside the six-yard box to pull a goal back for the visitors in the Midlands.

Expectations for Nkunku were sky-high from a Chelsea perspective; this was a man that came to England with a pedigree of scoring goals on a relentless basis for Leipzig. The Frenchman's next goal for the Blues came at Anfield over a month later in what turned out to be a consolation for the visitors, who were thumped 4-1 on Merseyside by Liverpool.

A handful of appearances after that before disaster struck once again for the terribly unfortunate Nkunku. Coming on in the 67th minute of Chelsea's Carabao Cup final defeat to Liverpool at Wembley, Nkunku completed almost an hour as the match went to extra-time. It was only his 10th appearance for the club since signing from Leipzig but a hamstring injury would see him ruled out until the last few games of the season.

Nkunku went on to miss another 14 matches for Chelsea in all competitions, leaving former head coach Pochettino frustrated with the Frenchman's fortune. "It's difficult for him," Pochettino explained. "When he arrived in pre-season, he was flying on the pitch and in training in America.

"Then he got the knee injury and now it's nearly eight months later. Even when he was ready to be involved again, he couldn't be the same as before. That is the risk.

"We have in our head the potential best Nkunku that everyone knows from the Bundesliga, but he can't be that player. That is why it is unfair to judge because the situations are completely different."

Nkunku did feature in the final four matches of his debut season for Chelsea but the 2024/25 campaign was earmarked as one where we could finally see why the Frenchman is one of European football's most-talked-about attacking players. A change in head coach perhaps did not help his case, with Pochettino being sacked and replaced by Enzo Maresca.

And it was Nkunku that scored the first goal - albeit an unofficial one because it was in a friendly - of the Maresca era. The France international opened the scoring for the Blues in Santa Clara, United States, against Wrexham in a pre-season friendly.

In the next game against Celtic and Club America, the forward was on target in both. Nkunku was massively impressive in pre-season despite being used in a number of different roles across the front-line.

"He can play everywhere," Maresca said on Nkunku back in July 2024 before a ball had even been kicked in the United States. "He's one of the players in these two weeks who is doing very, very well.

"He is taking the way we want to play. We will try to have players who can play in different positions [in attack]."

A few months on, however, it became clear to Maresca that Nkunku's best position - the one he could do the most damage in - was in the No.10 role behind the striker. "Probably the best moment from Christo for us was in pre-season," the Chelsea head coach said in late-November.

"For me, that was because he was playing in his position, which is a No.10 behind the striker, between the lines. Since we started the season, he is often playing as a nine for us. He also played the first Premier League game against Manchester City from the start as a winger, and we know that it's not his best position.

"We know that Christo's best position is between the lines as a 10, but Cole [Palmer] is playing there, and we are not going to play many games with Cole and Christo, or with Cole and Joao [Felix]."

That has been the issue for Nkunku this season, undoubtedly. Cole Palmer. Chelsea's star player; the man the team turn to when things are not going their way; the man that makes things tick.

Palmer was used on the right wing a lot under Pochettino and did a fantastic job but with Maresca in charge, the England international has predominantly been used in the No.10 role - essentially blocking a pathway for Nkunku to force his way into the team. While Nkunku is joint-top scorer alongside Palmer this season, with both netting 13 goals in all competitions, it has not once felt as if the France international is of the same value to this Chelsea team.

Just three Premier League starts since Maresca took over and that is why Nkunku has become increasingly frustrated with his role at Stamford Bridge. On Monday evening, news broke that Bayern Munich have been in contact with Chelsea over the potential signing of the Frenchman.

football.london understands the German club are seriously interested in the Chelsea forward, while the Blues are very keen on Bayern youngster Mathys Tel. Chelsea, though, have not offered Nkunku as part of a possible swap deal with Bayern.

It is looking more and more like Nkunku wants to call time on his 18 months or so with Chelsea and the club are open to doing business if it suits them. A move that had so much potential but will probably be deemed a 'flop' in years to come should the Frenchman leave Stamford Bridge. Shame.