There have been only 15 Premier League matchweeks since the start of the season, but plenty has changed.

Arsenal, rather than Liverpool, look the biggest threat to Manchester City's title defence, while Newcastle United are third ahead of the campaign resuming on Monday.

With the January transfer window also just around the corner, it is time to revisit Stats Perform's ranking of the top 20 most valuable Premier League players, first published back in July.

Inspired by Bill Simmons' NBA trade value list for The Ringer, this is not a ranking of the 20 best Premier League players but perhaps the 20 most difficult to sign.

The following factors have all been considered: how important these players are to their clubs, how replaceable they are, how proven they are, how likely they are to be sold now or in the near future, and how much they would cost if they were to move, influenced by ages and contract situations.

There have been some significant moves since the previous edition...

1. Phil Foden – Manchester City (July rank: 2)

Foden has gone from strength to strength at City this season, excelled for England at the World Cup and, in October, signed a new contract. There is no amount of money in the world that could convince City to sell the 22-year-old.

2. Reece James – Chelsea (12)

James is perhaps Chelsea's equivalent of Foden, their most talented academy graduate and still only 23. He was in excellent form to start the season before sustaining an injury that ruled him out of the World Cup. His big leap is more due to Chelsea's continued commitment to success under new owner Todd Boehly.

3. Erling Haaland – Manchester City (3)

There will always be speculation around Haaland's future, the existence or otherwise of any clauses in his contract and the suggestion he might hope to play for a Real Madrid. But he is not going anywhere just yet and is surely the form player in European football this season.

4. Kevin De Bruyne – Manchester City (4)

De Bruyne is now 31, making him by some distance the oldest player in the top five, and endured a miserable World Cup. However, the signing of Haaland has allowed De Bruyne to again showcase just how good he can be, thriving playing alongside a dead-eyed finisher.

5. Bukayo Saka – Arsenal (14)

The biggest star of Arsenal's resurgence has been Saka, who then also starred at the World Cup and was highly unfortunate to exit the tournament alongside his England team-mates. There will always be suspicions Arsenal will move on their best players eventually, but they are proving right now he does not need to leave to succeed.

6. Bruno Guimaraes – Newcastle United (15)

Another big jump takes Guimaraes up the rankings, having impressively built on his superb start to his Premier League career. Now an all-action number six, rather than a goal-getting box-to-box star, he has been linked to Real Madrid but appears committed to Newcastle, whose rapid progress should keep him happy.

7. Bruno Fernandes – Manchester United (7)

The Premier League's other big-name Bruno only narrowly trails Guimaraes, with Fernandes set to be United's undisputed main man following Cristiano Ronaldo's departure. It would likely only be United's failure to secure Champions League football that would see Fernandes consider his future.

8. Virgil van Dijk – Liverpool (5)

Four of the five Liverpool players on this list have fallen, although Van Dijk remains the Premier League's most valuable centre-back. Whether he is still the division's best at his position could be up for debate, however, with the Reds far less steady in defence this season.

9. Mohamed Salah – Liverpool (6)

Van Dijk's Liverpool team-mate Salah is 30 now and has slipped below his lofty standards at least in league play, scoring only six times so far this season. Liverpool will not rush to move on the winger, but they will be in trouble if this proves to be a sustained decline.

10. Harry Kane – Tottenham (10)

Spurs have seemingly guarded off interest in Kane from elsewhere, with potential suitors City happy with Haaland, but the arrival of Richarlison might also make them less reliant on the England captain than in previous years. He has still scored 12 league goals this season.

11. Trent Alexander-Arnold – Liverpool (1)

Alexander-Arnold has long had detractors outside of Anfield – including Gareth Southgate, who seemingly considers him England's fourth-best right-back. But this is the first time the 24-year-old's Liverpool performances have really been scrutinised. Regardless of Liverpool's stance, rival clubs would likely look elsewhere for a more complete full-back option.

12. Ederson – Manchester City (10)

Ederson slips only due to the number of top players on the rise. He is the most valuable goalkeeper in the Premier League, and City's playing style would have to alter considerably if the Brazil man was ever to depart.

13. Alisson – Liverpool (11)

Alisson is perhaps a better all-round goalkeeper than his Brazil team-mate, but he does not have the City star's same passing range, making him ever so slightly less valuable. In his 2022-23 form, Liverpool will not be looking for a change.

14. Darwin Nunez – Liverpool (17)

Nunez is one of the more difficult Premier League stars to gauge, missing some huge chances and sitting out matches through suspension but still netting at an impressive rate and showing signs of his enormous potential. He looks likely to be Liverpool's main man in years to come.

15. Son Heung-min – Tottenham (8)

Son has scored in only a single Premier League match this season, albeit he netted a hat-trick against Leicester City, and this first real dip in form could eventually see the forward lose his place at Tottenham given the competition for places.

16. William Saliba – Arsenal (new entry)

The first new entry is perhaps the Premier League's outstanding defender this season. Saliba has clearly benefited from three years away from Arsenal on loan, returning as a commanding centre-back, brilliant both on the ball and off it. His limited role for France at Qatar 2022 will take some explaining.

17. Martin Odegaard – Arsenal (new entry)

Another new entry and another key Arsenal man, Odegaard is Mikel Arteta's captain at Emirates Stadium and has started to show he might just fulfil the huge potential that was evident in his play as a teenager. Legendary status would be secured if he led the Gunners to the title.

18. Declan Rice – West Ham (16)

Rice has not quite been at his best for West Ham this season, but more importantly, his contract is winding down. It has been reported the Hammers have accepted their most prized asset will likely leave at the end of the season. Still, the fee should be huge.

19. Sven Botman – Newcastle United (new entry)

Botman, signed from Lille at the start of July, was not even in the Newcastle team when the season began. He is now a guaranteed starter in a side chasing Champions League football and perhaps more. Newcastle have no need to sell a centre-back who is yet to lose a match in black and white.

20. Mason Mount – Chelsea (13)

Committed to repeating the success of the Roman Abramovich era, Chelsea have no need to sell academy product Mount. But he still has not quite yet shown himself to be one of the Premier League's elite talents, netting only twice for a team down in eighth.