Borussia Dortmund pair Mats Hummels and Axel Witsel in contention to face Bayern Munich

Wolfsburg's Xaver Schlager vies for the ball with Borussia Dortmund's Erling Haaland. EPA

Borussia Dortmund's Raphael Guerreiro celebrates scoring their first goal. Reuters

Raphael Guerreiro celebrates scoring Dortmund's first goal. Reuters

Dortmund and Wolfsburg players observe a minute's silence in homage to the victims of Covid-19 pandemic. AFP

Bayer Leverkusen's Sven Bender and Kerem Demirbay in action with Borussia Moenchengladbach's Jonas Hofmann. Reuters

Moenchengladbach's and Leverkusen's players leave the pitch at half time. AP

Leverkusen midfielder Charles Mariano Aranguiz, left, and Moenchengladbach midfielder Florian Neuhaus vie for the ball. AP

Marcus Thuram of Borussia Moenchengladbach is challenged by Kerem Demirbay of Bayer 04 Leverkusen. Getty Images

Leverkusen's Kai Havertz, 3rd left, celebrates with teammates scoring. AP

Freiburg midfielder Janik Haberer (C) and Bremen defender Kevin Vogt and midfielder Maximilian Eggestein vie for the ball. EPA

Freiburg defender Manuel Gulde (R) and Bremen forward Joshua Sargent vie for the ball. EPA

General view inside the stadium during the match between Freiburg and Bremen. Reuters

Players observe a minute of silence to commemorate the victims of the coronavirus pandemic, prior to the match between Freiburg and Werder Bremen. AP

Dennis Srbeny (C) of SC Paderborn celebrates with teammates after scoring against Hoffenheim. EPA

Substitute players of Hoffenheim wear protective masks and watch the match from the stands. EPA

Paderborn midfielder Sebastian Vasiliadis (C) vies with Hoffenheim midfielder Sebastian Rudy (L) and defender Stefan Posch. AFP

Borussia Dortmund's Mat Hummels and Axel Witsel are winning their battles to be fit for Tuesday's top-of-the-table Bundesliga clash against Bayern Munich.

Victory for Dortmund at Signal Iduna Park would cut Bayern's lead down to a point with six games remaining.

Dortmund are already without injured captain Marco Reus and defender Dan Axel Zagadou, and the Ruhr Valley club know that failure to win could go some way to handing Bayern an eight successive title.

But manager Lucien Favre said central defender Hummels looks set to recover from a heel injury and fit-again midfielder Witsel was back in training.

Hummels was taken off at half time in Saturday's 2-0 win at Wolfsburg with a nagging heel injury. Belgium international Witsel has not played since the league restart 10 days ago.

"We will have to see at the last minute but I think it will be alright, 99 per cent Mats will be there," Favre said on Monday. "Axel trained yesterday with the team again and could be in the squad."

Dortmund will need all the help they can get against the in-form Bavarians, who like them have won six games in a row including the last two since the Bundesliga resumed following a break of more than two months due to the coronavirus pandemic.

With games played without fans for health safety reasons, Dortmund, who lost 4-0 at Bayern earlier in the season, will badly be missing the 80,000 crowd at their home stadium on Tuesday.

But Favre said the team was stronger now than earlier in the campaign, following the arrival of Emre Can and Erling Haaland in the winter transfer window.

"We do not think back to that first game. We have forgotten it. We did not play well," Favre said.

"We now play a system that better fits our squad and we have also brought in Emre Can and Erling Haaland as reinforcements in the winter who have further increased our quality."