His performances had convinced Liverpool that they were acquiring a potential superstar capable of becoming the creative heartbeat of their team. Naturally, supporters expected Wirtz to hit the ground running at Anfield.
However, his first season under Arne Slot failed to live up to those enormous expectations.
Wirtz Struggled To Replicate Leverkusen Form
Wirtz struggled to consistently produce the kind of performances that had made him such a sensation at Bayer Leverkusen. Although there were flashes of his quality, the German failed to establish the level of influence Liverpool supporters had anticipated.
And unfortunately for the midfielder, it has been more of the same during the early stages of his second season, this time under Andoni Iraola.
The continued struggles have inevitably increased the pressure surrounding Wirtz, with Liverpool legend Jamie Carragher among those to publicly criticise the midfielder.
For a player who arrived with such a huge reputation and an enormous price tag, the scrutiny was always going to be intense.
Yet there was another storyline developing among Liverpool supporters during those difficult moments.
Liverpool Fans Had One Wirtz Dream
As Wirtz struggled during his first season, many Liverpool fans inevitably wondered what might have happened if Jürgen Klopp had still been in charge.
There was a simple logic behind that thought.
Klopp had spent nearly a decade at Liverpool building an environment in which attacking players could flourish. His ability to develop footballers, create confidence and maximise their strengths was one of the defining characteristics of his tenure.
For some supporters, therefore, the dream was that Klopp would have found the formula to unlock Wirtz.
There was even the tantalising possibility that Wirtz could have eventually become Liverpool's answer to Manchester City's Kevin De Bruyne, a world-class creative midfielder capable of controlling games, producing goals and assists and becoming the attacking reference point of an elite team.
Of course, nobody can know whether that would actually have happened.
But now, remarkably, Liverpool fans are about to get a glimpse of that Klopp-Wirtz relationship after all.
Just not at Liverpool.
Klopp And Wirtz: The Germany Chapter
Klopp's appointment as Germany manager means the Wirtz-Klopp dream is finally set to become a reality, albeit through a completely different path.
The German national team will be Klopp's primary concern. His responsibility will be to build a winning side, establish his tactical identity and get the best possible performances from the entire squad ahead of the upcoming UEFA Nations League campaign.
But make no mistake: Wirtz will be one of the players Klopp will be watching particularly closely.
There is no reason to suggest Klopp will give Wirtz preferential treatment. International management is about getting the best out of the team, not individual players.
However, Klopp knows Wirtz extremely well as a player who was already one of the Bundesliga's biggest stars before moving to England. He will understand the qualities that made him so dangerous at Leverkusen and, perhaps more importantly, the confidence that allowed him to consistently display them.
That could be hugely important for Wirtz.
Klopp Could Restore Wirtz's Confidence
One of Klopp's biggest challenges with Germany will be ensuring that his attacking players have the freedom and confidence to express themselves.
For Wirtz, that could be exactly what he needs.
The midfielder's problem at Liverpool has not suddenly been a lack of footballing ability. The talent that made him one of Europe's most coveted young players has not disappeared.
What has been missing is consistency and the ability to translate that talent into decisive performances at the highest level.
Klopp could potentially help him rediscover that confidence.
And there is one obvious reason why Liverpool fans can expect Klopp to care about getting the best out of Wirtz, even if he would never officially frame it that way.
Klopp will forever be a Red.
The German manager's connection with Liverpool remains incredibly strong after his extraordinary nine-year spell at Anfield. He delivered the Premier League, Champions League, FA Cup and League Cup while transforming the club into one of Europe's most formidable sides.
Naturally, Klopp will now be focused entirely on Germany. But there is little doubt that he will want Wirtz firing for his country and also leave the international break as a player filled with renewed optimism and belief for his beloved former club.
And if he succeeds, Liverpool will undoubtedly benefit from it.
Liverpool Will Be Watching Closely
The upcoming Nations League fixtures therefore provide a fascinating subplot to Klopp's Germany debut.
For Germany, Wirtz's revival would be hugely valuable. For Klopp, getting one of his most talented attacking players performing at his best could be a major step toward building a successful national team.
And for Liverpool supporters, it could be the experiment they always wished they had seen at Anfield.
Klopp may not be able to coach Wirtz at Liverpool anymore, but he now has the opportunity to show exactly what he can get from the German superstar.
If Wirtz suddenly starts producing the kind of performances that made him a Bundesliga phenomenon, Liverpool fans may be left wondering one thing:
What if Klopp had been there all along?