It hasn't been an easy week for some of Bundesliga's top teams, with shocking results and with equally surprising resignations.

The German top flight has been considered lately as one of the most consistent in European football. Backed by its economical infrastructure, its teams often fight for the top European cups, and the most powerful sides are frequently involved in some of the best player's transfer rumors. But this week, things turned dramatically against some of their teams, and questions are still waiting to be answered. What is happening with the Bundesliga? Is it a "one-horse race" like some fans refer to it due to Bayern Munich's dominance over the years? Why are the teams involved in European competitions underperforming just like Borussia Dortmund or Bayer Leverkusen did? Here are some of the headlines this week left concerning the German top flight.

Bayern's awful loss against Porto

It's true that Guardiola's side has been struggling with injuries, but what happened against the Portuguese side was a matter of concern. The team's performance during the first ten minutes was baffling, with rookie mistakes made by Xabi Alonso and Dante, with the game's ref sparing the German champions by not sending off Manuel Neuer during the first minutes of the game. It's true, the Bavarians only need to score two goals against Porto to eliminate them, but it's also true that Bayern has faced this scenario four times in their European cup history -that is, hosting the second leg after a two-goal loss-, and the club coached by Pep Guardiola has never been able to rally back. Could this setback risk Pep Guardiola's job with the club?

Guardiola could not believe his team's defensive mishaps against Porto, which have them on the verge of elimination.

Jürgen Klopp's resignation

After Borussia Dortmund's baffling start this season, it seemed that some of the team's star players were set to leave the yellow and black side when the tournament ended, but no one saw Jürgen Klopp's resignation coming. One of the most praised coaches in Europe, the German boss stated he did not feel comfortable anymore with his role, and he was choosing to step aside. Even knowing that all things must come to an end, it seemed that Klopp's time with Dortmund had some chapters to be written yet, and his absence will only broaden the gap between those teams that fight for the second place and the eternal champion Bayern Munich.

Klopp surprisingly ended his 7-year stint as Dortmund's coach this Wednesday

Wolfsburg's capitulation against Napoli

One of this year's surprises in the Bundesliga was Wolfsburg. The green side took over Borussia Dortmund's place as the team that would give Bayern a hard time to win the championship, even defeating Guardiola's side 4-1 when the year 2015 began. After all the praises earned and with key contributions by Kevin De Bruyne and Andre Schürrle, the Wolves were seen as the top candidate to win the UEFA Europa League, but their crash and burn performance against Napoli was somewhat shocking to most fans. Will they be able to bounce back against a defensive maestro such as Rafa Benitez?

Not even Kevin De Bruyne could believe his team's fate in their Europa League defeat facing Napoli

Bayern's doctor resigns

If Pep Guardiola had his hands full trying to overcome their 3-1 loss against Porto, he will have to dedicate some time to stop a potential riot among his staff. Today, the team's chief medical officer Hans-Wilhelm Müller-Wohlfart resigned since he felt he was blamed by Guardiola for this week's loss against Porto, added to a gesture the Spanish manager directed at him while the team played against Bayer Leverkusen. Despite the doctor's claims, Guardiola spoke about the team's head of medical services during his press conference today.

"I was informed about his decision, and I respect it. Nothing happened between the doctor and me, I know that dealing with injuries comes with the job, the medical staff is not to blame," Guardiola said.

Doctor Müller (right) left his job with Bayern in 2008 since he did not get along with then-coach Jürgen Klinsmann.