Even though their opponents are not playing well, I don't think Dortmund will be able to perform much better in their upcoming match against Freiburg. If the club continues to sell great players without replacing them with anyone who is better, their performance will eventually get worse throughout the season, and Dortmund fans will become upset with the club.
Why should they not maybe perform better against the upcoming game at Freiburg ?
Selling players have nothing to do that they play one game good and then 2 games bad nor not good.
I guess that they for sure aware that they have to play better if they even want to beat Bayern Munich or any other Team.