bundesliga.com takes a look at why the Bundesliga is the playground of choice for the game's brightest young hopes.
It's almost like the proverbial London bus: you wait for a while and then two twinkle-toed youngsters with stardust in their boots come along at once. Except in the Bundesliga, you're not waiting all that long. And sometimes, there's more than two!
Matchday 18 was just one such occasion. Though Bayern's defeat to Borussia Mönchengladbach grabbed most of the headlines for its shock value, it wasn't the only jaw-dropping moment. Fifteen minutes from time, Wanner stepped off the bench aged just 16 years and 15 days to become Bayern's youngest-ever top-flight debutant, missing out on the Bundesliga record — held by Dortmund's Youssoufa Moukoko — by just two weeks.
"He's an unbelievable talent, very quick and very brave. He immediately took on [Breel] Embolo and went on dribbling when he first got on the ball," said Bayern boss Julian Nagelsmann. "Physically he's not bad either. But he has to remain grounded and clear in his head, then the doors will be open for him"
Just 24 hours later, a door opened for Raebiger, who joined Leipzig aged 10 and is now a teenager who might have had his debut under Nagelsmann last season had circumstances been different. He took Leipzig's policy of basing success on baby-faced brilliance to the n-th degree when he — at 16 years, eight months and 22 days — became the league's third-youngest debutant ever with a cameo in Die Roten Bullen's win over Mainz.
"Sid's extremely young, and even though it was 4-1, it's still not easy for a player from the 2005 generation," said RBL boss Dominic Tedesco, who took Dominik Szoboszlai off four minutes from time to give Raebiger his big Bundesliga break. "He's a good footballer, he always wants to have the ball, and you saw that today."
Wanner and Raebiger clearly have exceptional feet, though their feats are certainly far from exceptions. In fact, Lucas Copado - the nephew of Hasan Salihamidzic who turned 18 three days after the game - made his Bayern debut against Mainz, while 18-year-old Spanish winger Hugo Novoa and 19-year-old attacking midfielder Joscha Wosz were also on the pitch for Leipzig.
Of course, the pandemic has played its part in giving youngsters their opening: Moukoko aside, the other four players among the Bundesliga's all-time youngest debutants made their bows in the 2021/22 season. But the pandemic is only a temporary contributing factor to a permanent trend that has been over two decades in the making.
A sorry group stage exit from UEFA Euro 2000 led to German football taking a long, hard look at itself. The upshot of the soul searching was all 36 Bundesliga and Bundesliga 2 clubs were required to develop youth academies. With a combined 1.95 billion euros (2.2 billion dollars) spent on their grassroots infrastructure since 2001, they clearly listened.
But along with the money came the know-how. Youngsters were given twice as much training as before, while being encouraged to pursue their academic studies in tandem with their football education. With coaches and clubs at the cutting edge of football technology, analysis and innovation, the sea-change led to - by 2018/19 - players aged under 20 playing 5.5 per cent of Bundesliga games, a ratio two times higher than the English Premier League, Serie A in Italy and Spain's LaLiga.
The fruit of the policy is a constant stream - and at times a gushing torrent - of teenage upstarts starting up in the Bundesliga, and we are not simply talking squad players.
Wirtz is Leverkusen's golden boy now, but he followed Kai Havertz, who himself succeeded Julian Brandt as the BayArena's baby-faced darling. Dortmund brought through Mario Götze having made Nuri Sahin their - and for a long time the league's - youngest debutant while still 16. Thomas Müller was 18 when he made his Bayern bow on August 2008, Jamal Musiala - whom Wanner succeeded as the record German champions' youngest debutant - was 17 when he stepped into the limelight.
Naturally, given the success of Germany's national team and clubs on the international stage, the league's fresh-faced revolution has not gone unnoticed beyond the country's borders. It has meant players migrating to a league where they know their talent - spotted elsewhere but not exploited - would now be given a free rein to shine, and all in front of the biggest crowds in the world with Bundesliga games packing in 40,000 fans on average.
"It speaks for itself," Jadon Sancho told FourFourTwo magazine, when asked why he chose to join Dortmund from Manchester City at 17, blazing a trail for Bellingham & Co. "Youngsters get opportunities. You've got to thank Dortmund, because it's unheard of for a team that gets 80,000 at every home game to put so much faith in youngsters."
"I can't thank Birmingham City enough for what the club did for me - not just this season, but since I came to the club when I was seven," Bellingham said when leaving his hometown club to make the move to Germany aged 17.
"Now I'm really excited to join one of the biggest clubs in Europe. BVB's path, but especially how they help young players to improve, made the decision very easy for me personally and for my whole family."
Dortmund, of course, have been leading lights in rejuvenating the Bundesliga. Aged 16, Reyna followed fellow USMNT star Christian Pulisic to Dortmund where the now-Chelsea man made his Bundesliga debut at 17. Erling Haaland was 19 when he moved to Signal Iduna Park, the place where the 21-year-old Robert Lewandowski saw his future being best mapped out when he left Lech Poznan in 2010.
Of course, it helps that the men picking the teams are also barely too old to be on the pitch. In the case of the 34-year-old Nagelsmann, he is - some six years into his hugely successful coaching career - even younger than his captain, Manuel Neuer, and barely older than Lewandowski and Müller.
The Bayern boss is one of a quartet of Bundesliga coaches in their 30s - along with Tedesco (36), Wolfsburg's Florian Kohfeldt (39) and Hoffenheim's Sebastian Hoeneß (39) - while Serie A and LaLiga have two, and the English Premier League just one.
But even that trend isn't new. Thomas Tuchel was 35 when he took charge of Mainz in 2009, and followed Jürgen Klopp, who was only 33 when he took on the role as player-coach with the 05ers in 2001. The current average age of the 18 men on the Bundesliga benches is just over 45, but is by no means unique or even eye-catching: in 1989, it was just 41.
But age is just a number, right? "Of course I'm still young, but we will manage it. It's not a problem that Manuel Neuer's a few days older," said Nagelsmann, who is actually some 16 months the Germany captain's junior. "It's always a question of the way you talk to the players. It's about putting yourself in their shoes." On that front, Nagelsmann - a former defender whose career was cut short by injury - seems to have feet tailormade for the job.