Their current unfavorable ranking could be because of their less than optimal performance or because the strategy they are playing is not working well. It is difficult for them to be at the top of the standings because the points they have are quite far from the teams at the top of the standings, but with their journey still far away I think they can still improve their ranking including their performance such as the strategy that may need to be changed because I think the strategy they are currently doing is not suitable.
I didn't think they would be defeated by Stuttgart but in fact Stuttgart beat Dortmund by quite a large score, this is quite a big defeat for them, with their next match which will face Bochum I think they can win, as long as they can learn from the mistakes that occurred in the previous match which made them lose badly.
https://www.bundesliga.com/en/bundesliga/clubs/borussia-dortmundDortmund’s performance against Stuttgart in the weekend was very poor and I am very surprised they conceded that many goals against Stuttgart. It is certain that Dortmund are not in their best form this season, they are significantly below their form from the previous season. They seem weaker than Bayern Munich, and Bayer Leverkusen. I hope they can learn from their mistakes in this game and prepare to face Bochum.

Actually, can we say that Stuttgart is very good this year? They played fearlessly and very well against Real Madrid. They narrowed down the field against Borussia Dortmund. They humiliated them with 5 goals. Borussia is an important team for the Bundesliga and we usually watch them in the championship race. Nuri Şahin should prepare his students well.