Cole Palmer was named the eighth?best player in the world at the Ballon d'Or ceremony in September, but both data and the eye test indicate a dip in form.

The 23-year-old is still regarded within Chelsea as "untouchable". Former head coach Enzo Maresca labelled him the club's "best player" while his successor Liam Rosenior has held multiple meetings with his star forward since taking charge.

However, even by the reigning PFA Young Player of the Year's own admission, Palmer is not yet operating at his fluid, brilliant best - with several mitigating factors contributing to that downturn.

Firstly, as Professional Footballers' Association chief executive Maheta Molango said, the England forward has likely been suffering from burnout.

"When I look at someone like Cole Palmer, that's three consecutive summers without a break," Molango said at the Financial Times Business of Football Summit.

"People say he's a millionaire - yes, he is. But it doesn't give you an extra lung or an extra leg. I want to see Cole Palmer on the pitch because he's the one who makes me dream."

Three years without a summer off resulted in 112 games for club and country, with the addition of Club World Cup fixtures for Chelsea, the European Championship with England and the Under?21 European Championship before that.

Those managing him did not consider it a coincidence that as demands on Palmer increased, his fitness suffered. The forward began struggling with a painful, recurring groin issue at the end of last season.

He had only partially recovered by December, returning after more than six weeks out, and Chelsea's medical team continue to monitor him closely.

Asked by BBC Sport about Palmer's display following the 2–1 defeat away at Arsenal, Rosenior said: "He played 83 minutes. That was tactical.

"When I took him and Enzo [Fernandez] off, they were both on yellow cards and I wanted Garna [Alejandro Garnacho] and Liam [Delap] to come on and give us freshness, which I felt they did. He's absolutely fine to start the game [against Aston Villa] on Wednesday."

Even so, it may have been a surprise to some that Palmer - usually the source of goals or creativity - was withdrawn as Chelsea chased an equaliser. But the statistics suggest it was not an unjustified decision in the heat of the moment.

Palmer has seven goals and three assists in 16 matches since returning from the groin issue in December. However, four of those goals have come from the penalty spot.

Penalties have boosted Palmer's numbers throughout his career. Only former midfielders Mark Noble and Mikel Arteta have a higher proportion of penalties among players with 40 or more Premier League goals, compared with Palmer's current 40% ratio.

No player in the Premier League has scored more penalties than Palmer's 18 since his Chelsea debut in September 2023 - underlining why the man nicknamed 'Cold' is already viewed as one of the best finishers from 12 yards in the competition's modern era.

Palmer's form has dipped since his sensational 2024 calendar year. From his Chelsea debut to the meeting with Bournemouth in January 2025, Palmer scored 36 league goals (33% of them penalties) and provided 17 assists in 54 matches.

Since then, he has scored nine league goals (66% penalties) and registered three assists in 33 games. Palmer is taking fewer shots, creating fewer chances and posting lower expected?goals and expected?assists numbers across those two periods.

Interestingly, Chelsea have also shown they can compete without him.

Without Palmer, Chelsea have won 73% of their games this season compared with just 24% when he plays. They have taken 2.27 points per match without him compared with 1.18 with him and have improved from 1.5 to 2.2 goals per game in his absence.

They are curious statistics given Palmer's decisive performances in both the Conference League final victory over Real Betis in May and the Club World Cup triumph against Paris St?Germain in July, wins that confirmed his status as Chelsea's main match-winner.

At the beginning of last season, Chelsea rested Palmer for their pre?season tour of the USA, giving him the platform to start 36 Premier League matches during the 2024?25 campaign.

Palmer was mostly rested in the Conference League but played 556 of the 570 minutes available at the Club World Cup - in what he said were "difficult" conditions - while winning Fifa's newly expanded competition.

It led to a 336?day season for Palmer, despite him being afforded time off during pre?season.

Chelsea delayed the start of pre?season training but ultimately had only 35 days, the club's shortest ever break between seasons and two days fewer than the Covid?affected 2019?20 and 2020?21 cycles.

It was then that Palmer's painful groin issue worsened - something he has been trying to overcome during two separate spells, having been permitted time to train with his cousin, a personal trainer, in Dubai. Chelsea sources, both privately and publicly, have denied Palmer requires any surgical intervention.

After Chelsea's 3-1 win over Wolves in February, in which Palmer scored three times including two penalties, he said: "I am still not there physically but I hope with the medical staff here that I will come back and show my level again."

Chelsea's medical department, led by Australian Bryce Cavanagh, has succeeded in getting Reece James and Wesley Fofana playing regularly again, which bodes well, while Romeo Lavia remains a longer?term project.

The medical team's approach is one Rosenior appears to have bought into after Maresca left the club following a breakdown in relations with the hierarchy, said to have been sparked largely by a perception of medical staff meddling in first-team affairs.