This autumn, a comparison between the constitution of Borussia Dortmund and the condition of the left knee of defender Mats Hummels comes to mind.

The professional footballer is constantly struggling with problems with this joint, the painful patellar tendon, and yet Hummels is almost always in the starting line-up of coach Marco Rose.

“It's going in the right direction,” said the 32-year-old world champion from 2014 before the game against Ajax Amsterdam in the Champions League this Wednesday.

“Right now I feel good about it.” But he can't be absolutely sure that it will stay that way.

Too often he has experienced setbacks in working with his body. “Sometimes like that, sometimes like that” is what his knee is doing, the reactions of which depend not least on how well he is on the day, he said recently. These words can also be used to describe the performance of the Dortmund team, which has suffered many injuries and has to invest a lot in order to remain reasonably stable. As far as the results are concerned, it usually works well, and there may even be a connection between the state of the player's knee and the performance of the collective.

Hummels is a player who should help shape the essence of BVB under coach Marco Rose.

With his experience and intelligence he can support colleagues who need help under the influence of difficult moments, emotions and insecurities.

In the first leg in Amsterdam, however, he could not fulfill this task.

The cracking 0: 4 defeat left its mark on the picture that Borussia Dortmund gave in the current season, at least from the outside perspective.

Lessons from regression

The team seemed helpless, was overrun, and Hummels was also overwhelmed. When opponents invested a lot of energy, BVB's resistance has been broken again and again in recent years. "We had a team that too often let themselves be undermined by an opponent that was aggressive in a positive sense," said Hummels in an interview with Sport-Bild. However, that was much better last spring with the interim trainer Edin Terzic, now there is “more fire in it, more life”. However, Amsterdam was a step backwards.

However, this experience of total lack of chances did not have any consequences for the well-being of the team, claims Hummels: "Results from previous games really have no effect on the next game, you learn that in professional football." Such statements are certainly not only for them Public, but also addressed to the teammates, who should act as free as possible from fear of another Ajax assault.

Hummel's words carry weight.

On the other hand, he has to fight more and more for recognition on the pitch.

Manuel Akanji has been playing Konstanter for some time, whose player opening passes have now reached a level similar to that of Hummels' vertical balls.

The veteran is above all important as a personality and a haven of calm.

Or will Hummels still manage to play physically at the highest level over the long term?

In any case, he would like to return to the national team, where he paused after the European Championships due to his knee problems.

"I'm trying to get myself in even better shape," he replied when asked about the upcoming international matches.

"In the end, I'll be there when I'm needed, and if not, maybe I can rest a little."

National coach Hansi Flick will probably watch closely how Hummels acts against the agile Amsterdam attackers.

Because neither with the Dortmund defender nor in the case of his team is clear what is possible in the current season.

Is BVB able to play for the championship until the end of the season and also to reach the quarter-finals or maybe even the semi-finals in the Champions League?

Will Hummels stay fit and be in very good shape for a long time?

Or is the stability required for this over a whole year utopian?

These questions will not be finally answered in the second leg against Ajax Amsterdam (9:00 p.m. in the FAZ live ticker for the Champions League and at DAZN), but this game can provide a few pointers.

For the first time this season, BVB is under great pressure not to lose to a strong opponent.

Another defeat threatens a dangerous duel with Sporting Lisbon for a place in the round of 16, which the Portuguese could win in a home game against BVB at the end of November.