Creating Thomas Tuchel's 2016 Summer Blueprint for Borussia Dortmund

Thomas Tuchel has his work cut out for him this summer as he tries to sustain what he has at Borussia Dortmund and rebuild the squad as need be.

The head coach led BVB to become the best runners-up in Bundesliga history (78 points), but their failure to win the league, the DFB-Pokal and Europa League left their generally good overall performance looking to have been in vain. They just weren't quite good enough and will need to be even better next season in order to win trophies.

Tuchel's task will be made even more difficult by the fact captain Mats Hummels has left for rivals Bayern Munich and Ilkay Gundogan has departed for Manchester City.

Henrikh Mkhitaryan's future at Signal Iduna Park is also in question, with the Armenian having yet to extend his contract. His deal is set to expire in just over 12 months' time.

The most important step for Tuchel is to make sure Mkhitaryan signs a new, long-term contract at BVB. Regardless of the transfer fee the former Shakhtar Donetsk man could fetch, losing his best defender, defensive midfielder and attacking midfielder in the same summer would leave Tuchel with a near-impossible task if he is expected to win trophies.

Mkhitaryan's name has been most widely circulated in media reports, but it is similarly important BVB do not sell key players such as Marco Reus, Pierre-Emerick Aubameyang and Sokratis Papastathopoulos.

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Others, such as substitutes Moritz Leitner and returning loanee Jakub Blaszczykowski, can go. Even Adrian Ramos, despite his upturn in form late in the season, should be sold if a sufficient bid is tabled for his services.

Dortmund need to rebuild in the most sustainable way possible. That means adding quality to their first team and having substitutes who have a good chance of becoming starters or superior to their first XI counterparts in the likely event those players leave the club. Such a rotation is vital for a so-called selling club, and it's one thing that makes the job of a manager at such an outfit much more difficult than if he were at one of Europe's elite sides.

To this end, the signing of Ousmane Dembele was a real coup. The Frenchman has enormous potential and will not demand to start every match. He could be world-class by the time Mkhitaryan or Reus leaves. The signing of Mikel Merino follows this policy, and Dortmund have one of the most exciting academies in Germany—Christian Pulisic and Felix Passlack are stars in the making, and there are plenty more rising stars among the under-15, under-17 and under-19 teams.

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Dortmund absolutely need replacements for their departing stars, but finding someone to fill the roles of Hummels and Gundogan is just not an option. Both are, at their best, world-class. And the handful of players on their level will be simply unattainable for a club with BVB's budget.

Accordingly, Tuchel will have to look to add quality in other positions while replacing the outgoing superstars with players who might be at a somewhat lower level. One option is left-back, where Marcel Schmelzer—despite playing well by his standards in 2015-16 and recently penning a contract extension—is a limited player.

The influence of full-backs is incredibly underrated, but for Dortmund, a better option on the left side of defense could do wonders for Reus and the attack while still providing quality at the back. Ricardo Rodriguez is an option, with Swiss outlet Blick recently reporting BVB were interested in activating the Wolfsburg man's €25 million release clause.

On the right, Erik Durm can compete with Lukasz Piszczek for playing time. Both are injury-prone players, and Dortmund will therefore need more than simply Durm, Piszczek and Schmelzer as full-back options.

For Hummels' role, Tuchel could look internally to use Sokratis and one of Neven Subotic and Matthias Ginter as his central defenders. There is quality and potential among those options, but if he deems it insufficient, the trainer should look elsewhere.

Omer Toprak from Bayer Leverkusen would be a defender of proven quality who is familiar with the league. Dynamo Kyiv's Aleksandar Dragovic could be a good alternative. Both were linked to BVB in a recent Bild report, although Marc Bartra, per Bild, could also be a target. Niklas Sule would have been a good acquisition with an eye to the future, but a move for the 20-year-old seems out of the question after he recently stated, per Bild, he will remain in Hoffenheim.

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For Gundogan's role, Tuchel has had plenty of time to consider his recourse during the often-injured midfielder's spells on the sidelines. Gonzalo Castro has much in common with his compatriot in terms of playing style, even if he's not at the same level, while Nuri Sahin would be an alternative in more of a regista role. Bayern's Sebastian Rode could provide a bit more muscle in a box-to-box role and, according to Bild, is closing in on a move to Signal Iduna Park.

If Dortmund want a player who has the potential to be world-class, as Gundogan is, their best option is Youri Tielemans. The Belgian was considered part of Tuchel's plans in this aforementioned Bild report, and although he's perhaps not yet ready to start in every game (he only turned 19 in May), he could be a world-beater in the next few years. Many clubs will be after his signature, but given they managed to sign Dembele, BVB could well bring in the Anderlecht man.

Tuchel has his work cut out this summer. He needs to retain Mkhitaryan and replace Gundogan and Hummels, but can only truly do the latter by thinking to the long term. In that regard, Tielemans is probably the best bet for central midfield.

In defense, a player such as Toprak or Dragovic would be perfect, but Sule (if possible) and Ginter (if salvageable) would be even better. Left-back Rodriguez would be a good way for Dortmund to upgrade their squad and at least partially make up for the inevitable short-term loss in quality that will come with selling Hummels and Gundogan.

Dortmund have a huge task ahead of them if they are to replicate or improve upon their 2015-16 form. But Tuchel inherited a team in disarray and is capable of pulling teams from the ashes. Whether that will be enough to see Dortmund re-establish themselves in the Champions League and win a domestic trophy or two is another question.

@Mr_Bundesliga