Breaking Down What Raphael Guerreiro Will Bring to Borussia Dortmund

There were mixed feelings among the Borussia Dortmund faithful in April, when it was announced that Marcel Schmelzer had prematurely signed an extension to his contract.

Some were delighted to see loyalty from one of the club's longstanding servants, especially during a time in which it was uncertain as to whether any of Dortmund's stars had any intention of staying at Signal Iduna Park in the long term.

Others, however, bemoaned the deal as confirmation that a decent but limited player would remain Dortmund's starting left-back until 2021.

As events have unfolded, it seems that BVB will indeed retain Schmelzer for a few more years and will benefit from his experience and dedication to the team, but he may not even be a starter come the beginning of next season.

Dortmund's activity in securing their left-back position has not been limited to Schmelzer's extension: last week, they signed Raphael Guerreiro from FC Lorient for a reported (per Transfermarkt) €12 million.

The Portugal international may play the same position as Schmelzer, but he does so in an entirely different way and will bring a different dimension to the BVB team.

Schmelzer should be praised for his performance last season, which was consistently in the region of being at the peak of his career. He played to the best of his ability and did so within his means. The 28-year-old offered immense work rate, reliable defending and good crosses with his left foot.

The problem, however, was the aforementioned limit of Schmelzer's contribution. And while his gusto was useful under Jurgen Klopp, the more cultured football played under Thomas Tuchel didn't exactly suit the former FC Magdeburg man's game.

The way Tuchel prefers to play requires all his players to be involved in the attacking game or at least to be capable of such. And therein, Schmelzer's weaknesses come to the fore; his limited skill set makes him rather predictable (if the ball isn't on his left foot, he's mostly harmless) and his ball control is underwhelming at best.

There were times last season in which Tuchel played his chess match well, but there were clear weak points that hindered his team. For example, his use of Erik Durm in midfield against Bayern Munich in March was smart in that it added energy and intensity that neutralised the opposition going forward, but the converted full-back was a wasted player in situations in which Dortmund held the ball and were unable to break forward with pace. Similarly, Schmelzer was a case of a "wasted" player in attack, in that there just wasn't much he had to offer.

Guerreiro is an entirely different type of full-back. At 1.70 metres in height, he's much smaller and much less physically formidable than Schmelzer. He's not quite as tenacious in making his tackles and overall isn't as good a defender as his teammate.

On the other hand, Guerreiro is the kind of player who could be a winger on a lesser team. And actually, he played in a wide role ahead of a full-back more often than in defence over the last two years while at Lorient.

The 22-year-old is proficient with both feet and has a good first touch: He's not as prone to losing possession while trying to field a long pass as Schmelzer is.

It may seem like a small thing, but not making cheap giveaways is a form or preemptive defending. And Guerreiro is much more capable of serving as an auxiliary attacker than his teammate, which could make all the difference in Tuchel's possession-based system against opponents that defend deep.

Guerreiro can slip through defences and even has a decent nose for goal, having scored a couple times for Portugal in his early career.

In many ways, Guerreiro resembles his compatriot, Vieirinha. Like the Wolfsburg man, he's a converted winger; a smaller player with great skill on the ball, but who has developed just enough defensive skills to earn him a spot in defence in a team in which he might not have been deemed good enough to start in midfield.

The Portugal international has the potential to be a real star in Tuchel's team, but it depends on how he develops his defensive game. There are plenty of full-backs in world football who can defend, and plenty who can attack. But few can do both, and those are the elites (think David Alaba).

As it stands, Guerreiro will have an advantage over Schmelzer in most games, as Dortmund will be expecting to win and Tuchel will want to send out a strong attacking side first.

Schmelzer, meanwhile, will most likely start the tougher games against elite opposition, in which his defensive prowess and aggressive style of play will be useful. Guerreiro may eventually take that role too, but it all depends on how he develops. Having only turned 22 in December, he still has room to grow and could be remembered as a very important signing to an ever-changing Dortmund side.

@Mr_Bundesliga