BERLIN (AP) -Schalke can deal another blow to Borussia Dortmund's stuttering title defense in the Bundesliga's fiercest local derby on Saturday.
Dortmund already trails Bayern Munich by nine points after seven matches following the Bavarian team's perfect start. Schalke is seven behind in third place.
Bayern would become the first team to start a Bundesliga campaign with eight victories by winning at Fortuna Duesseldorf.
"Nobody can really be surprised that Bayern would be so strong," Dortmund captain Sebastian Kehl said in Thursday's edition of Kicker magazine.
Also Saturday, second-place Eintracht Frankfurt hosts Hannover, Borussia Moenchengladbach visits slow-starting Werder Bremen, Bayer Leverkusen hosts Mainz and Freiburg visits troubled Wolfsburg.
"Now is finally the time for the first win at home this season," said Wolfsburg coach Felix Magath, whose team is second from the bottom. "The opponent doesn't matter."
On Sunday, Nuremberg hopes to end its four-game losing run at home against Augsburg, and Stuttgart travels to resurgent Hamburg looking for only its second win. Stuttgart striker Cacau was ruled out for at least three months Thursday after injuring his left knee in training.
Last-place Greuther Fuerth kicks off the eighth round at Hoffenheim on Friday.
On each of the three previous occasions a team has started the Bundesliga with seven wins - Bayern in the 1995-96 season, Kaiserslautern in 2000-02 and Mainz in 2010-11 - Dortmund has recovered to win the title.
Bayern has scored 21 goals and conceded only two so far, but Kehl insists the league leaders can be caught - even if Schalke was to win the 141st Ruhr derby on Saturday.
"Then we'd still have 26 games to make up for it," the midfielder said. "Otherwise we could give up already ... We're still beginning the season. A lot can still happen."
Kehl, Mats Hummels and Sven Bender returned to training on Wednesday after recovering from injury, but coach Juergen Klopp still has concerns over defender Marcel Schmelzer and midfielder Ilkay Guendogan, while playmaker Mario Goetze (thigh injury) and Poland captain Jakub Blaszczykowski (left ankle) are definitely ruled out.
"We've been preparing for the derby for two weeks. Unfortunately, we didn't know with which players," Klopp said Thursday. "I still haven't made any final decisions on the line-up."
Schalke also has injury concerns, with attacking midfielder Julian Draxler laboring with a wrist injury and Greece defender Kyriakos Papadopoulos definitely out with chicken pox.
Schalke coach Huub Stevens said Thursday that he also had doubts over striker Chinedu Obasi and defender Christoph Metzelder.
Security will be tight for the game, with a ban on glass bottles in place at the stadium to cut down on possible injuries and vandalism.
Dortmund, which hosts Real Madrid in the Champions League on Wednesday, is unbeaten at home in 17 games.
"Fear is a poor advisor," Stevens said. "You have to have respect."
Bayern defender David Alaba marked his return to competitive action by scoring and setting up two more goals in Austria's 4-0 win over Kazakhstan on Wednesday. But there are still questions over the fitness of Netherlands winger Arjen Robben, who is still laboring with muscular problems in his thigh.
"We have to remain calm and take the pressure off," Bayern sporting director Matthias Sammer said. "It has to go step by step."