Ralf Rangnick made an unlikely heretic. His rimless eyeglasses and charcoal sport coat gave him the air of a serious, but benevolent, schoolmaster. Standing in front of a live studio audience, he looked just a little uneasy. He seemed to take comfort in the familiarity of his only prop: a tactics board dotted with pale magnets.

It was, by some distance, the biggest platform Rangnick — then 40 — had ever had. He was the coach of modest Ulm, in Germany’s second division. His host, the leonine Michael Steinbrecher, had a far greater profile, and his program, “Das Aktuelle Sportstudio,” was a national institution.

Rangnick’s appearance lasted five minutes or so, but the ideas he elucidated were explosive. Coolly, surgically, he railed against many of the abiding tenets of German soccer. It was not exactly well received. “There was a big reaction,” Rangnick said.

He was derided for his lack of playing career, dismissed as nothing but “book smart.” He was nicknamed, with a sneer, the “football professor.”

Hindsight has been far kinder. That interview took place in the winter of 1998. Looking back, Rangnick appears less a maverick and more an oracle. The approach he laid out on that flimsy tactics board — zonal marking, a back four, fierce and organized pressing of the opposition — has become the bedrock of soccer in the touch-screen age.

Seeing the Future

There is a reason Rangnick ranks as, quite possibly, the most intriguing free agent on soccer’s coaching market. There are plenty out there who are younger, or who have lifted more trophies, or who could command a higher salary, or who see their names linked to the world’s most prestigious clubs with confidence-inflating regularity. There are very few, though, who can justifiably claim to have had a greater impact on the game than the man widely regarded as the high priest of pressing.

The tendrils of Rangnick’s influence spread far beyond the parvenu clubs — Hoffenheim, Red Bull Salzburg, RB Leipzig — that he has turned into mainstays of either the Bundesliga or the Champions League.

His protégés — the likes of Marco Rose, Adi Hütter, Sebastian Hoeness and Julian Nagelsmann — have embedded his school of thought at teams across the Bundesliga. The dominant style of German soccer now — the one exported beyond the Bundesliga’s borders by the likes of Thomas Tuchel and Ralph Hassenhüttl — is the style Rangnick advocated two decades ago.

Many of the methods he pioneered have traveled even further. Rangnick, for example, was one of the first coaches to abide by the “eight-second rule,” the idea that most goals are scored within a few seconds of winning the ball back. The idea is now part of most coaches’ baseline thinking.

“Five or 10 years ago, you were not afraid of what the other team was doing while you had the ball,” he said. “Now most teams in most leagues have some sort of plan for how they can hurt you when they do not have possession.”

The greatest proof of the triumph of his ideas, though, is in the nature of Liverpool and Bayern Munich, the reigning English, German and European champions. A host of players at both clubs encountered Rangnick at some stage of their development. Bayern’s assistant coach, Danny Röhl, is a Rangnick student. Jürgen Klopp, the Liverpool coach, co-opted much of his thinking at an early stage of his career.

Rangnick considers Klopp to be “the best coach in the world,” one who has taken the beliefs they share onto another plane of excellence. A straight line can be drawn from the ideas Rangnick espoused 22 years ago to the pressing game that has become not only the hallmark of Liverpool and Bayern, but also soccer’s best practice, its dominant orthodoxy. What Rangnick explained to that live studio audience was the game’s future. It just did not know it yet.

The Communion of Ideas

Rangnick has been invited back onto “Das Aktuelle Sportstudio” a dozen or so times since his debut. Every appearance now is something of a coup.

Though Germany’s relationship with Hoffenheim and RB Leipzig, the teams with which Rangnick is most intimately associated, remains uneasy, nobody holds his lack of playing career against him anymore. “If you look at the Bundesliga, the vast majority of coaches did not play at the very highest level,” he said.

Despite his vindication, though, he has no great wish to reverse engineer a sense of destiny onto his story. The way he tells it, his rise is pockmarked with coincidences. There was the day, as a player, he won man of the match in a game in which all he did was mark the opposition’s star. “I asked myself,” he said, “what did you actually do today, other than spoil it for him?”

There was the time the amateur team he was coaching was summoned to play a friendly against Valery Lobanovsky’s Dynamo Kyiv. “I was sure I’d made a mistake, that I’d named one player fewer,” Rangnick said. “Because it seemed to me they definitely had more people on the pitch.”

And there was Germany’s decision in the late 1990s to invest heavily in its youth system, combined with its failure on the international stage at the European Championships in 2000, which created the conditions in which his brand of soccer — and coaches without an illustrious background — could thrive.

That interpretation of his own story is significant when it comes to considering the future of the game he has helped to shape. It is possible to read soccer’s history as a battle of ideas, where each strategy that rises to prominence is, sooner or later, first neutralized and then countermanded by a new one.

Or it is also possible to see it — as Rangnick does — less as a tale of conflict between systems and more one of communion between them. As far as he was concerned, he was simply building on the work of the likes of Arrigo Sacchi, the great A.C. Milan manager, as well as Lobanovsky.

What comes next, in his mind, will not overturn the orthodoxy he helped establish, but build on it. He is particularly intrigued by how teams use set pieces. A third of goals come from corners, free kicks and throw-ins, he said. And yet a third of training time is not dedicated to their practice. He does not believe the pressing era is the end of history. It is just another start.

The Next Frontier

Rangnick watched the triumphs of Liverpool and Bayern over the last two years with a sense of satisfaction. Not simply out of affection for those players and coaches at both clubs whom he counts as friends, but because they demonstrated how far his ideas could go.

“Lionel Messi is the best player in the world,” he said. “But even he is not resistant to the press. Look at what happened against Liverpool and against Bayern: If you play in unison, as a team, then even he had no solutions.” The collective, working correctly, trumps the individual.

To present Rangnick — or Klopp or Bayern Munich’s Hansi Flick, for that matter — as nothing but a preacher of pressing, though, is to misunderstand the nature of the revolution. “It is a very important part of the game as people like me and Jürgen see it,” he said. “But it is only a part of it.”

A friend of Rangnick’s provides the analogy: The pressing is the fruit, the visible product, but the work goes on in the roots. Not just in coaching the players — to teach squads “to find the right decisions in congested situations, and under pressure” — but in every element of the club.

Rangnick transformed the way his teams played — either as a coach or as a technical director — because he transformed the structure behind them. He left Red Bull in the summer, but a much-anticipated move to A.C. Milan never materialized. Wherever he lands next — ideally, he has said, in England or Germany — he will expect to do the same.

At Leipzig, players were expected to arrive at the training facility 90 minutes before a session started so they could undergo saliva and blood tests; within 30 minutes, Rangnick and his staff would know how much the players would train that day, and how hard. They tested for allergies — gluten and lactose — and tailored their players’ diets. They brought in an expert to help teach them how to maximize their sleep.

This data, he said, will be the next frontier, as much as anything on the field. Success and failure in soccer will depend on the quality of information teams have, and the quality of the experts they have appointed to provide it and to decipher it.

Throughout his career, he has not only leaned on analysts, but educated them in what sort of analysis they need to provide. Scouts were trained to know what to look for, to have a clear idea of the sorts of traits in players that worked well in his teams, or the sorts of coaches who might suit them.

“We had a clear profile of the types of coaches we needed, a concrete profile of the type of player we wanted for every position on the pitch,” he said. “If you know exactly what you need, it becomes quite simple.”

There are a handful of clubs he sees, around Europe, that currently meet those criteria for success. One is RB Leipzig. That, perhaps, should be no surprise, given that it is built in Rangnick’s image. He wonders if Paris St.-Germain warrants inclusion. Bayern Munich and Liverpool most definitely do.

It should be no surprise that all of them have German coaches, ones who bear just a little of Rangnick’s imprimatur, ones who see soccer as he does. This, to his mind, is what the future of soccer looks like. He has seen it once. He believes he can see it again.