The news was good yet the atmosphere seemed somewhat subdued. The Borussia Dortmund CEO, Hans-Joachim Watzke, was delivering an update on the club’s financial situation – record turnover of €400m (£364m) for 2016-17 and an astonishing profit of €134m since 2011 – but no one appeared to be that interested. There was only one story in town and that whether Ousmane Dembélé was going to join Barcelona.

In the end the 20-year-old Frenchman joined the Catalan club for £96.7m and while that will make Dortmund’s figures even prettier next year it has severely diminished the club’s chances of challenging at home and in Europe, where they kick off their Champions League campaign against Tottenham Hotspur at Wembley on Wednesday. In fact, the whole saga has completely overshadowed an already turbulent summer and it is only now that the new manager, Peter Bosz, knows what kind of a squad he has at his disposal.

That is not unusual in itself, with clubs all over Europe recalibrating after the last days of the transfer window, but few clubs will have lost a bigger talent than Dortmund. Add to that the tension that surrounded Thomas Tuchel’s last few months at the club and the terrible attack on the team bus in April that shocked the whole club and left the defender Marc Bartra out injured for a month and it is clear that it has been a hugely testing year for everyone.

The main problem with the Dembélé move was not that he joined Barcelona – it was anticipated he would leave at some point – but that he had been at the club for only a year. Apart from that, he had been the perfect Dortmund signing: a young, talented player who had been given a chance in the first team, excelled and seen his value increase beyond all dreams.

It is what Dortmund do best and to give them their credit, they had worked incredibly hard to sign Dembélé. They had been in contact with him for a long period, telling him how much they rated him and that he would get his chance in the starting XI immediately. “Dortmund showed their interest in me from a very early stage,” he said when he joined, “and were in close contact with me throughout – and that behaviour really impressed me. I knew that they would look after me.”

The Dembélé signing in May 2016 was only one of several triumphs for the club in the transfer market. Over the past few years they have established themselves as the No1 club for young players to be nurtured.

This season Bosz has no fewer than 10 players aged 23 or younger in his first-team squad. When the Swedish wonderkid Alexander Isak was leaving AIK in January 2017 he chose Dortmund ahead of Real Madrid. The 17-year-old Jadon Sancho left Manchester City for the Bundesliga club during the summer while Dan-Axel Zagadou, an 18-year-old French defender, felt similarly out of the first-team picture at Paris St-Germain and he too opted for Dortmund.

All three must have been encouraged by the chances given to Dembélé and Christian Pulisic, the young American forward who has played 41 times in the league for Dortmund despite being only 18. Zagadou has already played three times for the first team.

Dig further and there is an array of talent at the club’s youth teams as well, with Janni Serra, Dzenis Burnic, Jan-Niklas Beste and Manuel Pherai, whose adviser is none other than Mino Raiola, among the players the club have high hopes for.

As for the here and now, Dortmund have started their league season with two wins and a draw. They travel to London in good spirits but with a mounting injury crisis. The club captain, Marcel Schmelzer, has been ruled out for several weeks with an ankle problem and Bartra is a doubt with a thigh injury, also suffered in the 0-0 draw against Freiburg on Saturday.

Add to that the long-term absentees Marco Reus, Raphaël Guerreiro and André Schürrle and the fact that the club’s best midfielder, Julian Weigl, is just returning from a lengthy time on the sidelines and the challenge facing Bosz is pretty clear.

Jadon Sancho opted to join Borussia Dortmund from Manchester City this summer. Photograph: NurPhoto/NurPhoto via Getty Images

So far the former Ajax manager has given Pulisic the chance to replace Dembélé to the right in a front three and he has responded superbly. Pierre-Emerick Aubameyang still leads the line despite interest from Milan this summer with Maximilian Philipp, a £17.5m signing from Freiburg, on the left, although another summer arrival, the Ukrainian Andriy Yarmolenko, could start at Wembley.

Either way, this season should really be one of transition considering the loss of Dembélé and the fact that a new manager is in place. Dortmund, however, have surprised before and try telling the ultra-competitive Bosz that they will not challenge this season.

But no matter how they end up doing, the future is bright for Dortmund and they are an example to many a club. They have a long history of giving young players a chance and they will continue to do that.

As Lars Ricken, the 1997 Champions League winner who is the head of youth development at the club, recently said: “Promoting players from our own youth teams, such as Pulisic, Felix Passlack, Schmelzer, Götze, Reus or Nuri Sahin, who have now reached almost legend status, is for Borussia Dortmund’s identity extremely important.”