A significant few weeks lie ahead in the future of Conor Gallagher.

Mauricio Pochettino said in early January he had received assurances from the Chelsea hierarchy that selling players would not be a prerequisite to new signings in the January market. All very nuanced.

And yet, as the transfer window rumbles on, Gallagher's position feels precariously unstable - mooted as a player capable of attracting big money to balance the books.

Here, Sky Sports analyses Gallagher's merits and why Chelsea may be foolish to let a homegrown talent leave the club at such a crucial juncture in Pochettino's early rule.

With Chelsea again enduring an underwhelming season, Gallagher has been one of the few bright spots. Often elevated to the role of captain by Pochettino, the midfielder's statistics show why he is deserving of the responsibility.

Paired with Enzo Fernandez and Moises Caicedo - players that both cost more than £100m - Gallagher, the academy graduate, has outshone them both.

The 23-year-old established himself in the Premier League with eight goals and five assists on loan at Crystal Palace in the 2021/22 season and, while he may not be on course to match those numbers, he is still first among all Chelsea midfielders per 90 minutes in the top flight for assists, chances created, final-third passes and take-ons.

But Gallagher is not just the primary attacking force in Chelsea's midfield - he also excels at the defensive side of the game.

Again, the England international ranks above Fernandez and Caicedo for duels and possession wins. Those numbers highlight the disappointing starts the South American pair have made to their Chelsea careers - but also show why Gallagher has become vital alongside them.

Pochettino has been steadfast in his portrayal of Gallagher as paramount to the Chelsea cause. It's easy to see why. As already spotlighted, Gallagher is indispensable in terms of Pochettino's playing style.

The Argentine's intention and identity are clear, if on-pitch execution remains a little off. But that's no fault of the tireless Gallagher, who is the heartbeat of this inexperienced side.

He plays the role of enforcer expertly, roughing up opponents - he's conceded at least 13 more fouls than any other player in the league (47) this term - before mocking them with a bypassing run or perceptive pass.

Speaking exclusively to Sky Sports in December, Pochettino reiterated his fondness of the Cobham academy graduate after he blossomed in a more senior role, saying: "He's one of the captains and I'm so happy with him. If Conor is playing for me it means he's performing; it means he's a player we count on. He's in our plan."

Whether that was a plea to Chelsea's owners remains unclear but it's hard to see how the Blues, and Pochettino himself, can afford to lose such an asset.

Shared history is something you simply cannot replicate. Gallagher is in Chelsea's DNA - he's been on their books since the age of eight and it shows in his performances. You can tell by the way he celebrates any win, big or small, and pains a loss. It's personal.

In tough times, he's often like a one-man mission: as others down tools, the result seemingly beyond them, Gallagher can be seen pushing on, attempting to rescue the situation at any cost. Chelsea don't have many players willing to do the same.

Tottenham are circling - attracted by his doggedness - and perhaps the easier option would be to quit. Make the short journey from west to north London in pursuit of a fresh start. But that's not in Gallagher's nature: besides, Chelsea still have plenty to play for.

Part of the Gallagher appeal is the commitment he demonstrates on a weekly basis, which compliments his ability to subtly dictate.

And yet, Gallagher is far from a luxury player. He drives this Chelsea side on and should be a model for every young hopeful wishing to make a career as a Premier League midfielder.

One thing's for sure, you can bank on a backlash should he be sold this month. Does reward outweigh the risk?

So, if Gallagher has captained Chelsea in more than half of their games this season, is statistically their best midfielder and is clearly in his manager's plans, why are the club open to selling him?

In short, it's about the money.

January 15 may not be an especially meaningful day for most football fans but it will be marked with a big 'X' on the calendars of Premier League clubs, as it's the day they are informed if they have complied with profit and sustainability rules (PSR) for the previous season.

As Everton have shown, failure to comply with what is essentially the Premier League's version of financial fair play can have serious consequences, and there are doubts over whether Chelsea have done so.

But even if the Blues do meet PSR requirements this year, their accounts for the current season and beyond may already be causing concern. This is because Chelsea are absent from the Champions League and are likely to remain without European football for at least another season given their mid-table status.

Without money rolling in from UEFA and with a spend of more than £1bn in the last three transfer windows, raising money from the sale of academy graduates such as Gallagher becomes a very real consideration.

This is because they cost nothing to buy, so the entire transfer fee can be listed in clubs' accounts as profit.

The same is true of Mason Mount and Trevoh Chalobah, also graduates from Chelsea's academy. It's no coincidence that Mount was sold last summer and that Chalobah looks set to follow sooner rather than later, while the window to sell Gallagher is closing given he has just 18 months remaining on his contract.

It's an unfortunate - some would say ugly - aspect of the modern game that clubs may feel incentivised to develop their own players so that they can be sold to balance the books.

It's also true that Chelsea's spending has inadvertently put them in this position, whereby one of their brightest and most popular players may be sold just when they need him most.

It's not the vision that was sold to Chelsea supporters when Todd Boehly and Behdad Eghbali arrived - but the owners may decide to suffer the inevitable backlash from losing Gallagher if it helps to prevent serious penalties in the future.

Who will be on the move in the January window?

Opening on January 1 and closing at 11pm on February 1 in England and midnight in Scotland, keep up to date with all the latest transfer news and rumours in our dedicated Transfer Centre blog on Sky Sports' digital platforms.

You can also catch up with the ins, outs and analysis on Sky Sports News, including daily transfer shows, and listen to our dedicated Transfer Talk podcast.