Two weeks and three days after breaking his arm during a game, Lionel Messi will dress for Barcelona in Tuesday’s Champions League game.

He hasn’t been “medically cleared” to participate, according to his club, but one assumes that at Barcelona there are three ways of doing things: The right way, the even better way and the Lionel Messi way. So despite the brevity of the layoff, he’ll play if he wants to play.

Conspiracy theorists in the Spanish media have suggested Messi may want to make one last impression before FIFA World Player of the Year voting closes on Friday.

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Unless he or she suffers from some form of amnesia, it is difficult to imagine any professional soccer observer letting Messi, 31, slip their mind.

In fact, Messi’s absence has had the opposite effect. It’s made him more remarkable and – this once felt impossible – more indispensable. Where does soccer go after him?

Someone put the question to Napoli manager Carlo Ancelotti the other day. Based on his employment history, Ancelotti may be the most plugged-in man in the game. He’s won the league in four different countries with nine teams over a quarter century. He has no discernible style, as such, but a long streak of cunning that has allowed him to roll with changes. He is so much out of time that he always seems right in the middle of it.

So when Ancelotti says Paris Saint-Germain and France forward Kylian Mbappé is the next great one, you mark it down.

“[Mbappé] is a credible candidate to take the place of these champions [Messi and Cristiano Ronaldo] who win all the trophies,” Ancelotti said.

(Ancelotti also name-checked Neymar, but after his widely lampooned play-acting at this past summer’s World Cup, the Brazilian may some day be just as great, but he will never be anywhere close to as loved.)

Mbappé, 19, is a different sort. Like Messi, he appears to have been designed by some celestial marketing department – born to be famous and adored.

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Like Messi, he was a childhood prodigy. Like Messi, he was identified as the next big thing in his early teens. And like Messi, he was making an impact on the world stage before he was old enough to vote.

Mbappé was the standout star of the World Cup. Now that the professional season has begun, he’s been ever better.

It is difficult to make like-for-like comparisons in France’s Ligue 1 because PSG’s Qatari-backed funding tips the scales so far in their favour.

But taking that into account, Mbappé has been ridiculous – 11 goals in eight league games (two fewer than he had all of last season) and a couple more in the Champions League. He was benched for a recent game because he’d shown up late to a team meeting. Three minutes after being subbed on in the second half, Mbappé scored the game winner.

He has that glow about him – that he can do whatever he likes on the field.

Of course, this was the thing that defined Messi. There was the constant sense that he was just about to do something incredible, even while he wasn’t doing very much at all.

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He’s still got that. The soccer metrics site, WhoScored, rates Messi as Europe’s (and therefore, the world’s) best player this season. His speed hasn’t diminished, as it does for so many other forward players when they enter their 30s. If possible, he looks even fitter than ever.

He still plays on the best team in the world. He is still surrounded by the finest talent on a roster that is eerily harmonious at all times.

Every once in a while, you will tune in to a Barcelona game, remark on someone you hadn’t heard of before (this year, its been 22-year-old midfielder Arthur Melo) and think, “Well, he looks like just about the best player alive.”

Messi’s company has that effect. It turns very-good-to-great players into legends. His ability to stitch together overlapping generations of Barcelona talent into a monolithic, nearly unbeatable collective may in the end be his finest legacy.

That’s why people – even those who don’t care all that much about soccer – get a little panicked whenever he leaves for a while. Even a dabbler realizes that watching Messi and Barcelona over the past 10 or 12 years has been a once-in-a-lifetime experience. We may see his like again – athletes in every discipline are only getting better, and always will be – but we never will on a team like Barcelona.

It is the whole that makes Messi’s individual part so appealing.

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In terms of any coronation to come, there’s only one satisfactory way to make the inevitable transition. Mbappé has to play for Barcelona.

There will probably be a spot opening up on the roster. Barcelona’s deep investment in Mbappé's French colleague, Ousmane Dembélé, hasn’t worked out. Were Dembélé sold on to another super-club, he would net a nice down payment on Mbappé.

He cost PSG $268-million a year ago. Given his potential (to sell replica jerseys), Mbappé might now be the world’s first half-billion dollar player.

Barcelona is one of very few who could afford it. I would go so far as to say they can’t afford not to do it.

Because even worse than the idea of Messi fading away is the vision that he might do so in a way that wasn’t fitting. Deciding when he will hand off the mantle, and then being able to do so to a teammate, would be, like everything else Messi does, too perfect.