Domestic duty takes center stage after the midweek distraction of the Champions League with several Bundesliga sides desperate to kick-start their seasons. Hamburger SV's new coach faces a tough debut against defending champion Bayern Munich, while Schalke, Stuttgart, Wolfsburg, Hertha Berlin and Freiburg are also winless after three games. Borussia Dortmund coach Juergen Klopp returns to Mainz, and Wolfsburg hosts a Bayer Leverkusen side sore after losing its first game of the season. Here are some things to know ahead of the fourth round of games:

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HAMBURG'S HOPE

Having made its worst start to the Bundesliga in any of its 51 seasons, Hamburg fired Mirko Slomka and promoted under-23 coach Josef Zinnbauer in his place this week.

Zinnbauer, Hamburg's fifth coach in three-and-a-half years, has the job "until further notice" and his immediate brief is to steer the side away from the relegation zone. Hamburg is scoreless in three Bundesliga games and bottom of the table.

Chairman Dietmar Beiersdorfer is hopeful that history can be repeated. As sports director in October 2004, he promoted under-23 coach Thomas Doll to the top position. Doll saved the club from relegation, then qualified for the Champions League the following season.

A good start could make all the difference for Zinnbauer. Bayern visits on Saturday.

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PATELLA PROBLEMS

Bayern appears to be getting into gear after its hard-fought 1-0 win over Manchester City on Wednesday. The club's opening Champions League game of the season featured two players, Rafinha and Mehdi Benatia, who'd barely trained with their teammates but who contributed to an overall team effort.

"We presented ourselves as one," Bayern sports director Matthias Sammer said.

There are fresh concerns over Franck Ribery, however. After scoring in his 23-minute cameo against Stuttgart last Saturday, the Frenchman's only appearance of an injury-troubled season, he broke off training Monday with a recurrence of his knee problem, an inflamed patellar tendon.

Ribery already sat out two-and-a-half weeks in August with the same issue, just after he'd been sidelined by back problems.

"It makes me sick," said Ribery, who will definitely miss Saturday's trip to Hamburg. "I don't know how long I'll be out for."

There are fears he could be out as long as teammate Bastain Schweinsteiger. The Germany captain has been resting for weeks with the same patella problem.

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LEVERKUSEN AT A LOSS

A loss to Monaco in the Champions League and a draw with Werder Bremen have taken the wind out of Leverkusen's sails somewhat. The side had previously won all five competitive games under new coach Roger Schmidt, only for inefficiency in front of goal to cost it dearly in both games.

Leverkusen had been praised for its exciting play and relentless pressure but questions are now being asked, particularly after conceding three goals to Bremen.

"The whole discussion gets on my nerves," striker Stefan Kiessling said after Leverkusen's first defeat of the season. "First you're praised and now it's already being questioned whether this 'hurrah football' is effective. I find it stupid."

Leverkusen visits Wolfsburg on Sunday, when the home side will be desperate for its first win of the season.

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DORTMUND DWINDLING

Despite missing a host of established regulars — midfielders Marco Reus, Shinji Kagawa, Jakub Blaszczykowski, Ilkay Gundogan and Nuri Sahin, and defenders Lukasz Piszczek, Mats Hummels and Oliver Kirch — Borussia Dortmund outplayed Arsenal for a 2-0 win to kick-start its Champions League campaign on Tuesday.

Midfielder Sebastian Kehl suffered a groin strain and is doubtful for Saturday's visit to Mainz, but the remaining players are high on confidence and Italian striker Ciro Immobile claimed his first goal against Arsenal.

Still, Dortmund coach Juergen Klopp is getting impatient with his growing injury list.

"If the other guys could hurry up with their returns it would suits me very well. We don't have many variation options any more," said Klopp, who is sure to receive a warm welcome at his former club.

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SEASON SPARK?

Schalke hopes its gritty 1-1 draw at Chelsea will be the spark that gets its season going after a disappointing start. Coach Jens Keller was coming under increased pressure after the 4-1 loss at Borussia Moenchengladbach and manner of that defeat last Saturday.

Schalke was knocked out of the German Cup by third-division Dynamo Dresden and has just one point from three Bundesliga games.

But the encouraging Champions League performance in London, achieved without nine regulars including injured captain Benedikt Hoewedes, is fueling optimism that the side may have turned the corner.

"It was a good start. Now we have to produce such performances in the league," said midfielder Julian Draxler, looking ahead to Saturday's home game against Eintracht Frankfurt.