Jupp Heynckes has insisted his age will not be an issue after returning for a fourth stint in charge of Bayern Munich at 72, joking that he will go for the Germany job when he reaches 80.

Heynckes will begin his latest tenure on Saturday when Freiburg visits the Allianz Arena, as the Bavarians look to bounce back from consecutive league draws under the dismissed Carlo Ancelotti.

Bayern goes into the match five points behind leader Borussia Dortmund after seven matches, and some have questioned whether the experienced coach will be up to the task. But Heynckes has no worries about his advancing years or the fact he has been out of coaching since 2013, claiming his mind is more important than his legs as a manager.

"My age is not relevant," he told reporters. "But it is not about the rest, for me it is about fitness, professionalism and motivation.

"The mind is often more important than the legs. When I'm 80, I'll think about replacing Joachim Loew (as Germany coach)."

Heynckes has had the international break to work with his players and believes they are beginning to enjoy themselves again, but he did have a warning for the defence.

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"It was a very busy week and I had to get back to it, but I knew that," he said. "Everyone said that there was a good atmosphere and that the players are enjoying work again.

"But we have a lot of hard work to do. We have to work out a lot, we have to play football again, have self-confidence. We have to work hard.

"In the last three games, the team conceded seven goals, which is a lot. For me it is essential to be stable defensively - that the coordination between the team players is right and that everyone cooperates defensively."

James Rodriguez has endured a difficult adaptation to life in the Bundesliga and Heynckes is keen to bring the best out of the Colombian.

"He's a good boy, but it's difficult for him to come to another culture and go from 0 to 100," he added. "I'll take care of him - I think he'll be a great help."

Heynckes also confirmed that Arturo Vidal, who endured a disappointing international break with Chile, has returned to Bayern with a "slight" injury and will not be risked against Freiburg.

"Vidal has a slight muscular problem and will not play tomorrow. I am a coach who takes no risks and Arturo is important to us," he commented.

"The frustration, the long journey - they will have contributed to the injury, but he is working well."