Transfer windows across Europe finally closed on Monday, but that does not mean questions over the future of a number of Premier League players have been answered.
Key names at some of the country's biggest clubs have less than a year remaining on their contracts, with extensions to those deals yet to be signed.
In less than four months' time, those players can be approached by European clubs who want to sign them on free transfers at the end of the season - meaning the Premier League sides will miss out on potentially huge transfer fees.
Sky Sports News has picked out four of the Premier League's most high-profile players who could be targeted by Europe's elite in January - and what their exits would mean.
David de Gea
Manchester United supporters were treated to the news in July that David de Gea was set to finally end the speculation over his future and sign a new, long-term deal at Old Trafford worth up to £375,000 per week.
The contract would have made him the highest-paid goalkeeper in the world but, two months on, it is yet to be signed.
No reason for the delay has been given, meaning that, while De Gea is still United's undisputed No 1, he is free to talk to new clubs in less than four months' time.
In July, Ole Gunnar Solskjaer said: "As I've said a few times, I think that will be up to David and the club to announce if it happens - if and when."
De Gea has played every minute of United's four matches so far this season, conceding four goals and recording one clean sheet.
He showed a concerning repeat of last season's dip in form when he allowed Patrick van Aanholt's stoppage-time winner to go under him at the near post in United's shock 2-1 home defeat against Crystal Palace.
However, Solskjaer still trusts De Gea, and he has captained the side on three occasions already this campaign.
When De Gea does leave Old Trafford - whether that is next summer or further down the line - he has a legitimate claim to go down as one of the Premier League's greatest ever goalkeepers.
The Spaniard is only the fifth keeper to record 100 clean sheets in the competition's history, and of the Premier League's current crop, only Joe Hart sits above him in the standings.
Would he be missed?
It is hard to think of a player in United's squad that they would miss more, were they to leave, than De Gea. The fact he could do so for free in less than 12 months' time will be of great concern to Solskjaer and executive vice chairman Ed Woodward.
The 28-year-old has been named United's player of the year on four occasions - nobody has been handed the award as many times.
While United do have two credible replacements - Sergio Romero and Dean Henderson - already on their books, neither is of the calibre of De Gea.
Romero has played just seven league games in four years at Old Trafford, while Henderson is just four games into his first top-flight campaign during a loan spell at Sheffield United.
One comforting factor for Solskjaer, should he lose De Gea, would be that Woodward has repeatedly shown a willingness to spend big in the transfer market - something that would be necessary to buy an adequate replacement.
Christian Eriksen has made no secret of the fact he has been considering a move away from Tottenham. In July, just a month after Spurs tasted defeat in their first ever Champions League final, the Denmark international suggested he had reached the stage in his career where he was ready to "try something new".
Manchester United and Real Madrid demonstrated interest this summer but a move failed to materialise, while he has shown no inclination to perform a U-turn and sign a new contract in north London.
In August, Mauricio Pochettino said: "The player is not affected about the rumours. There is nothing to say because we have one year more on the contract, but it is not the best situation for him and for everyone."
Despite failing to commit his future to Tottenham, Eriksen has featured in all four of their matches this season. However, Pochettino started him on the bench for two of those - including the opening-day win over Aston Villa - perhaps signalling a desire not to rely on a player who has so far been unwilling to sign a new deal.
Eriksen has still been able to demonstrate his importance to Spurs, though, scoring in the derby draw with Arsenal last weekend. Tellingly, Pochettino's side are yet to score this season without the 27-year-old on the pitch.
Eriksen was a key player for Tottenham last season as they memorably reached the Champions League final and once again secured a top-four place in the Premier League.
To underline his importance, he recorded more Premier League assists for Spurs than any other player for the fifth time in the last six seasons.
So creative was Eriksen, in fact, that only Eden Hazard and Ryan Fraser registered more assists than him in the league in the previous campaign.
Would he be missed?
Eriksen's ability to consistently provide more assists than anyone else at Tottenham since arriving from Ajax in 2013 is more than enough evidence of why he would be missed if he does leave for free next summer.
Should that situation come to pass, Spurs would likely have to pay a premium to bring in a replacement of comparable quality - something chairman Daniel Levy has rarely shown a willingness to do.
However, the north Londoners do possess another high-quality creative midfielder in Dele Alli, while they have the option to buy Giovani Lo Celso from Real Betis next summer if he impresses on loan this campaign.
Like De Gea, Callum Hudson-Odoi seemingly ended question marks over his future when it emerged in July he had agreed a £180,000-per-week deal to stay at Chelsea. But like De Gea, that deal is still waiting to be signed.
If that was not concerning enough for the Blues, Bundesliga club Bayern Munich are known admirers of the 18-year-old - having already had four bids turned down this year - and would be ready to pounce if he entered January with just six months remaining on his deal.
In July, Frank Lampard said: "He is a player that came through the academy; he is a player that can be a big player for Chelsea and for England. We - as a club, for sure - want him to stay."
Hudson-Odoi is yet to play for Chelsea this season as he continues his recovery from the Achilles injury he suffered against Burnley in April.
However, he returned to training several weeks ago and a return could follow shortly after the current international break.
Hudson-Odoi's struggles to break into Maurizio Sarri's Chelsea team last season were well publicised, but the Italian was eventually unable to resist the calls to unleash the teenage winger.
He made a total of 24 appearances for the Blues as they won the Europa League and finished third in the Premier League, scoring five goals and assisting five more in all competitions.
Hudson-Odoi's impact was so impressive, in fact, that Gareth Southgate handed him his England debut against the Czech Republic in March.
Would he be missed?
If Chelsea were unable to hold onto Hudson-Odoi, it would have a negative impact both on and off the pitch for the Blues.
With talisman Eden Hazard now at Real Madrid and experienced duo Willian and Pedro into the final years of their deals, Chelsea will need Hudson-Odoi in the short and long term.
In addition, new head coach Frank Lampard has already shown his willingness to place his trust in youth, which means an academy graduate as talented as Hudson-Odoi has a very good chance of establishing himself as a first-team regular at Stamford Bridge when he returns to fitness.
Getting him to turn down interest from a club the size of Bayern and commit his future to the club would also be a ringing endorsement of Lampard's project.
The one saving grace for Chelsea should Hudson-Odoi choose to walk away next summer, though, would be they will have money to spend. This season's transfer ban has restricted their expenditure, while they still have the windfall from the sale of Hazard burning their pockets.
Ryan Fraser has not played his hand in public as of yet, but the fact is he can leave Bournemouth for free at the end of the season as things stand.
Eddie Howe has already admitted he cannot guarantee Fraser will be at the club next season, although the fact Arsenal's interest in the Scotland winger appeared to cool as this summer's transfer window went on could boost the Cherries' hopes of keeping him.
In July, Eddie Howe said: "I never make guarantees to anybody. It's football and you never know what can happen.
Fraser remains a key figure for Bournemouth and has played in all five of their matches so far this season, recording one assist. The 25-year-old has played every minute of their 2019/20 Premier League campaign to date.
Arsenal's interest in Fraser this summer came as no surprise following his stunning 2018/19 campaign. He has been at the Vitality Stadium since 2013, but last season was a breakthrough for Fraser as he recorded 14 Premier League assists - only new Galactico Hazard had more.
It was the second time in the last three campaigns that Fraser led the way for assists in Eddie Howe's team.
Would he be missed?
As well as providing a steady stream of chances for his team-mates, Fraser has also chipped in with goals for the Cherries, finishing as their joint-third highest league scorer in the last two seasons.
If Fraser were to exercise his right to leave Bournemouth on a free transfer next summer, his absence would not just be felt by his club on the pitch.
If he were under contract, Fraser would be sure to attract a substantial fee. Losing him for nothing would be a bitter pill for Bournemouth to swallow, while they do not have as much money as the top-six sides to recruit a comparable replacement.
Other players out of contract next summer
- Toby Alderweireld - Tottenham defender
- Jan Vertonghen - Tottenham defender
- Nemanja Matic - Manchester United midfielder (option of an additional year)
- Eric Bailly - Manchester United defender (option of an additional two years)
- James Milner - Liverpool midfielder
- Nathaniel Clyne - Liverpool defender
- Willian - Chelsea winger
- Pedro - Chelsea winger
- Olivier Giroud - Chelsea striker
- Fernandinho - Manchester City midfielder
- Christian Benteke - Crystal Palace striker