For starters, it is not beyond the realms of possibility that he stays at Paris Saint-Germain and signs a new contract even more lucrative than the one he is on now. Another alternative is to see that deal out and join Real Madrid as a free agent next summer and take advantage of the hefty signing-on fee that comes with such a move.

A third option is to sign for Saudi Pro League club Al Hilal, who are reportedly offering the 2018 World Cup winner and current France captain a one-year deal worth €700million (£602m; $772m), before deadline day on September 1 and then go to Madrid on a free this time next summer once that contract expires. A fourth possibility is that Madrid are tempted into paying PSG a fee for Mbappe before the end of this window.

Whatever Mbappe decides to do, his bank account is going to benefit massively.

There are no two ways about it: the numbers being bandied about here are grotesque and will take player wages to a new level of obscenity, but if we’re being honest they lost all meaning a long time ago.

Saudi’s Public Investment Fund (PIF), the sovereign wealth fund that is now the majority shareholder in Riyadh-based Al Hilal, is willing to spend €1billion (£860m; $1.1bn), of which €300m (£258m; $331m) would be paid to PSG as a transfer fee, to acquire Mbappe’s services for a single season.

The transfer fee alone would be a world record, comfortably surpassing the (£190.3m; $245.8m) PSG paid Barcelona to sign Neymar in 2017.

Lionel Messi turned down a €1.2billion (£1bn; $1.3bn) two year-contract from Al Hilal last month to instead join Inter Miami in MLS. Meanwhile, his long-time rival Cristiano Ronaldo is being paid £175m ($226m) a year by Al Hilal’s Riyadh neighbours Al Nassr.

When you consider Trevor Francis, who passed away on Monday, became the first £1million ($1.3m at current exchange rates) British player in 1979, moving from Birmingham City to Nottingham Forest, the money involved in the possible Mbappe transaction seems even more astronomical.

Kieran Maguire, the football finance expert, has worked out that Francis’ 1979 fee today, when revenue increases over time as a measure of purchasing power, would be worth £253.5million ($327.3m).

If this is taken into the current context, Al Hilal’s offer that would see £258million go to PSG does not seem so unreasonable.

Very sad to read of the passing of Trevor Francis, recall him destroying Brighton at Maine Road.

His 1979 transfer fee, adjusted for football inflation (revenue increases over time as a measure of purchasing power) would be £253.5 million today. That’s how good he was.

The fee Al Hilal are seemingly ready to pay is also roughly the same figure that Real Madrid, who Mbappe could then join as a free agent in 2024 after bolstering his bank balance with a season in the Middle East, are spending to extensively rebuild their famous Bernabeu stadium.

So, yes, the finances involved here are off the scale, especially when his potential salary is broken down and you realise Mbappe stands to earn £1.65million a day. In that sense, it is not a surprise to see the negative reaction it has generated from a general public going through a cost of living crisis.

But when you compare these figures to what other top athletes earn, is it entirely out of kilter that Mbappe, one of the biggest stars in the most popular sport in the world, could command such a salary?

Tiger Woods, for example, turned down a reported $800million (£620m) last year to join the PIF-funded LIV Golf breakaway tour. Rory McIlroy, another of golf’s biggest names, is similarly said to have turned down an astronomical signing-on fee that stretched into the hundreds of millions of pounds when he chose to stay with the PGA Tour.

The common factor in the cases of Mbappe, Woods and McIlroy is that the money on the table came from Saudi Arabia.

But lofty sums can be earned in golf away from the Gulf, too. Brian Harman of the U.S. won The Open Championship on Sunday, pocketing $3million (£2.3m) for his efforts. The winner of this year’s FedEx Cup tournament, the culmination of the full 2023 season’s events on the North American-based PGA Tour, will be rewarded with a cheque for $17m (£13.2m).

Away from golf, but sticking with North America, franchises competing in the National Football League (NFL), National Basketball Association (NBA) and Major League Baseball (MLB) are not shy when it comes to handing out big-money contracts.

The immediate caveat to point out here is that all three of those leagues are closed shops, where relegation or qualification to earn further prize money in a Champions League equivalent do not exist, which makes any investment safer.

Jaylen Brown has just signed the richest contract in NBA history, with the Boston Celtics agreeing to pay the 26-year-old $304million (£235m) over five years. The extension kicks in for the 2024-25 season, and means his annual salary will jump from $28.5m (£22.1m) to $60.8m (£47.1m).

This surpasses the previous NBA record — set in 2022 — that saw the Denver Nuggets, another part of Arsenal owner Stan Kroenke’s sporting empire, commit to paying Nikola Jokic $264million (£204.5m) in a five-year deal. Jokic led Denver to win the 2022-23 NBA title last month.

According to Spotrac, a website that breaks down contracts, LeBron James, who is regarded as one of the best NBA players ever, will have accumulated $530.9million (£411.2m) throughout his career if he remains at the Los Angeles Lakers until the end of the 2024-25 season.

James, now 38, reacted to the Mbappe news by posting a GIF on Twitter of Tom Hanks’ movie character Forrest Gump, implying he would run to Saudi Arabia if he was offered a similar one-year contract.

On a similar theme, Usain Bolt, still the men’s 100m world record-holder despite retiring in 2017, joked he would be ready to make a comeback at age 36 if the Saudis are throwing money on the table.

Switching to the NFL, Patrick Mahomes, quarterback of the reigning champions the Kansas City Chiefs, signed a 10-year deal worth up to $503million (£389.7m) in 2020.

Although no quarterback has signed such a long-term contract since then, the annual value of what they earn goes up each time one of the game’s top players at its most important position gets a new deal.

Earlier this summer, Lamar Jackson agreed one worth $260million (£203.3m) over five years — $52m (£40.3m) a year — with the Baltimore Ravens, only for the Los Angeles Chargers to sign their quarterback, Justin Herbert, to a $262.5million (£203.2m) extension of the same length on Tuesday.

Herbert’s annual salary is likely to be eclipsed by that of Joe Burrow, who is set to receive a new deal from the Cincinnati Bengals. The expectation in the industry is that Burrow will become the highest-earning NFL quarterback on a per-annum basis.

Shohei Ohtani, a rare baseball player who excels as both a batter and a pitcher, could secure a contract worth $500million (£387.3m) if he hits free agency. His current contract with the Los Angeles Angels expires when the 2023 MLB season ends in November.

In boxing, there are significant one-off payments to be earned.

Floyd Mayweather, who retired undefeated in August 2017, called himself “Money Mayweather” due to the vast pay-per-view earnings he generated. A single fight against Manny Pacquiao in May 2015, for example, reportedly made the American around £225million ($290.5m). There was a similar payday two years later when he faced Ultimate Fighting Championship (UFC) star Conor McGregor in a cross-sport bout that was the last of Mayweather’s career.

Mbappe, should he accept Al Hilal’s offer, will become the highest-paid player of any professional sport.

Athletes, more so than ever before, are becoming brands in their own right, and the Frenchman comfortably sits alongside the biggest names in football. He is one of the few players in the sport, a list which also includes Manchester City striker Erling Haaland, who can legitimately replace Ronaldo and Messi and take on the mantle of being at the forefront of the world’s most popular game.

The people running the PIF know this and can sense an opportunity to take the Saudi Pro League to another level in terms of interest. And when you take into account what other athletes get paid, even though their earnings are spread across multi-year contracts, elite sport is awash with money.

Mbappe would just be the latest in a long line to cash in on their worth as both a professional athlete and a brand.