On May 23, 2017, Real Madrid announced the signing of the 16-year-old Vinicius Junior from Flamengo. Just over a week before, he had signed a new deal at Flamengo which included a reported buy-out clause of €45 million.

He sometimes plays like a pixelated trickster in a video game. Perhaps that ostentatious streak endeared him to Real Madrid.

In March, the Brazil Under-17s were beating their Paraguayan counterparts in the South American Championships as Vinicius grappled for control of the bouncing ball. The clock showed 30 minutes. With opposition defenders bearing down on each of his shoulder blades, Vinicius flicked the ball over his head and swivelled, eliminating both of them from the game. The No. 11 on the back of his shirt disappeared from view. Another Paraguayan thundered towards the ball. Calmly, Vinicius repeated the trick, knocking the ball over the defender's head with a swift movement of his right foot, before laying it off to his full-back.

Brazil won the 2017 edition of the Championship. And with seven goals and the Player of the Tournament gong to his name, Vinicius was the star.

Vinicius has become the prominent symbol of Real Madrid's emphasis on signing the best teenage footballers in the world. Martin Odegaard was the first high-profile manifestation of this ploy. Odegaard -- whose name is often accompanied by the cloying 'wonderkid' prefix -- joined Madrid in 2015 after a speed-dating tour of Europe's elite clubs. He is currently on loan at Heerenveen.

A similar pattern of recruitment looks set to continue. Alan and Lincoln -- two of Vinicius' teammates in the Brazil youth team -- are reported targets. A verbal deal for the former is already agreed, according to the press in Madrid. Valencia's Ferran Torres -- who was part of the Spain Under-17 team that lost to England in the final of the World Cup last month -- has also adorned the back pages.

This transfer strategy has been referred to as the "pre-emptive signings" plan. Diario AS Editor Alfredo Relano has set out his rationale for it: "the way to avoid missing out on the next Kylian Mbappe is to sign him when he's barely out of nappies."

It is natural to view pre-emptive signings as a prudent alternative to the Galactico experiment that defined Florentino Perez' first spell as the president of Real Madrid. Perez bought Zinedine Zidane, Luis Figo, Roberto Carlos, David Beckham, and Ronaldo to the club. His plan was to pay expensive fees for the best ready-made players in the world. That would allow Madrid to win everything.

A pre-emptive strategy delivers potential, rather than Bernabeu-ready players. Yet it still carries a significant risk, especially considering that Real Madrid spent €45m on Vinicius Junior -- a player who made his professional debut less than a fortnight before the transfer took place.

The signing of Vinicius broke two rules established by Simon Kuper and Stefan Szymanski in their co-authored book "Soccernomics," in which they apply data analytics to football to provide rough pillars of transfer-market prudence.

Firstly, don't sign a player following impressive performances at an international tournament. Their price is likely to be inflated, while specific incentives and tactical context mean their tournament performance may not be an accurate indicator of future performance.

Secondly, buy players in their early 20s to avoid problems of players not developing properly.

Alongside pre-emptive signings, Real Madrid are employing a parallel strategy. Theo Hernandez represents this secondary line of attack. He was 19 years old when he joined from city rivals Atletico. Yet his strong performances with Alaves in La Liga reduced the risk of the signing. Tangible proof showed that he had developed mentally and physically to a level that would allow him to contribute to Real Madrid.

Alvaro Odriozola of Real Sociedad and Kepa Arrizabalaga of Athletic Club are both linked to Madrid. And both have similar profiles to Theo. They are in their early 20s, and while not yet fully mature, have excelled in La Liga.

A pre-emptive action is defensive. It is an action taken against a possible future occurrence. In this case, that occurrence is the possibility of a talented young players joining one of Real Madrid's rivals before then going on to flourish. Real Madrid's pre-emptive approach appears to be as much about denying rivals the opportunity to sign young players as it is about signing suitable prospects for Real Madrid. The club will be better served by the transfer policy that looks inwards to what the squad needs, rather than outwards to thwarting what others want.