People still haven't forgotten about Jürgen Klopp's Borussia Dortmund outfit. Around a decade ago, the German outfit made waves across Europe, developing a reputation for thrilling offensive football, exciting young players and intense pressing.
Under Klopp, BVB won the Bundesliga on two consecutive occasions while also reaching a Champions League final in 2013. Borussia Dortmund hasn't won its domestic league since those glory days, with that side going down in history as one of the most electrifying teams of the past 20 years.
While in charge of the North Rhine-Westphalia side, Klopp favored 4-2-3-1 as his go-to system, with Robert Lewandowski up front and a trio of Mario Götze, Marco Reus and Kevin Großkreutz often behind him. It was highly effective, but 4-3-3 has been in place throughout his time at Liverpool.
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Dating back to 2016, the Reds have formed a 4-3-3 shape for the most part, with a false nine flanked by two pacey and direct wide threats who are intent on scoring goals and delivering in the final third.
It has worked for many years, with Liverpool securing a countless number of trophies, from the Premier League to the Champions League and all of the rest, but Klopp's squad dynamic is changing.
The 55-year-old has Mohamed Salah, Darwin Núñez, Cody Gakpo, Fábio Carvalho and Harvey Elliott already at his disposal and in the past week, Diogo Jota and Roberto Firmino have returned to full fitness, taking part in team training.
Klopp now has a wealth of attackers to choose from and it seems Luis Díaz will enter the fray before too long, after pictures emerged of him on the training ground. The South American has been absent since picking up a serious setback against Arsenal in October, but he now looks to be on the mend.
![Photo by John Powell/Liverpool FC via Getty Images](https://i2-prod.liverpool.com/liverpool-fc-news/features/article26262050.ece/ALTERNATES/s615b/0_GettyImages-1430075414.jpg)
The Colombian international could open up the prospect of Klopp potentially ditching his favored 4-3-3 for a Dortmund-style 4-2-3-1 ahead of the business end of the season, with that formation including an extra attacker at the expense of a third midfielder.
Díaz prefers to play on the left wing but Gakpo and Núñez have both occupied that spot over the past month. Klopp will have heavy competition for offensive places once his number 23 returns, which is why 4-2-3-1 could be considered.
In such a scenario, the team's midfield two would be expected to provide more of a cautious presence from deep, managing the middle third and presenting the team with a foothold over proceedings.
Such duties would be very different to what Klopp's midfielders are typically expected to do within his signature 4-3-3 system, as they are usually required to run up and down the pitch from penalty box to penalty box, which can be very physically taxing.
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![Liverpool manager Jürgen Klopp.](https://i2-prod.liverpoolecho.co.uk/incoming/article28219150.ece/ALTERNATES/s615/0_GettyImages-1748470251.jpg)
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Liverpool's midfield department is aging and the players involved have looked tired and worn for most of the season, which explains why the Reds are ninth in the table and perhaps captures why a more disciplined midfield duo could benefit the players at the moment.
The shift would also present Carvalho with hope. He thrived as a number 10 for Fulham last season ahead of his move to Anfield, but failed to even make the bench in Liverpool's most recent win over Everton. The young starlet knows 4-2-3-1, but he has seemed out of place when used as part of the 4-3-3.
Overall, considering how the make-up of Klopp's squad has changed this season, while also factoring in the impending return of Díaz, the long-awaited switch to 4-2-3-1 could be just around the corner.