Fingers are being pointed at Pep Guardiola after Bayern Munich's doctor of almost 40 years, Hans-Wilhelm Mueller-Wohlfahrt, left the club in the wake of their 3-1 Champions League quarter-final first-leg defeat to Porto.

The 72-year-old, who had been at Bayern since 1977, resigned along with his medical staff on Thursday night saying they had been held responsible for team defeats, and that there had been a deterioration in confidence in the backroom.

Catalan coach Guardiola has deflected questions at press conferences in recent weeks by saying "ask the doctor", and with stars Franck Ribery, Arjen Robben, Philipp Lahm and Bastian Schweinsteiger all in the sickbay on Wednesday, tension between the two was reportedly at breaking point.

Guardiola said on Friday he had the greatest respect for the departed doctor and refused to apportion any blame.

"When a player gets injured it's not the doctor's fault," he told a press conference.

However, Guardiola recently overruled Mueller-Wohlfahrt in the case of Thiago Alcantara, sending him to Barcelona for treatment on a long-term injury.

Mueller-Wohlfahrt, who briefly departed Bayern in 2008 after falling out with then-coach Jurgen Klinsmann but returned following the ex-Germany striker's departure, tantalisingly told Bild on Friday he "would tell all, but it's too soon right now."

The club itself said they accepted the doctor's resignation with regret and thanked him for his "first-class" service over the years.

His methods were called into question in recent times when Ribery received cortisone injections in his back to the general surprise of the French Football Federation medical team.

In the wake of that row the player stunned France by not only pulling out of the 2014 World Cup, but also retiring from the French team.

Athletics superstar Usain Bolt has often worked with Mueller-Wohlfahrt, with the Jamaican waxing lyrical about the German doctor's injection methods.