RB Leipzig will be without key defender Dayot Upamecano for Sunday's away Bundesliga match at resurgent Fortuna Duesseldorf after the burly French centre-back suffered a knee injury in training.

"It was an unfortunate clash between 'Upa' and (France Under-21 defender) Nordi Mukiele," said Leipzig coach Ralf Rangnick.

"At first it looked dramatic - the initial suspicions were that it was a cruciate ligament rupture, which has not the case, so there is a bit of fortune in the misfortune."

Rangnick says he expects the 20-year-old Upamecano, fourth-placed Leipzig's chief centre-back, to be sidelined for only a few weeks.

In his place, club captain Willi Orban is expected to return in the starting line-up after injury.

"It's not good for us, because Dayot's form has been good, but we have a few options in Willi Orban, Nordi and Stefan Ilsanker," added Rangnick.

He said Leipzig will also be without injured Portuguese midfielder Bruma while playmaker Emil Forsberg is over an groin strain he suffered in October, but is lacking the fitness to play at Duesseldorf.

Leipzig need a win after losing 1-0 at home to leaders Borussia Dortmund last Saturday when Axel Witsel scored the winner after 19 minutes.

However, Fortuna have turned their own fortunes around, escaping the relegation places with a six-game unbeaten run which included a shock 2-1 win over Dortmund - the leaders' only Bundesliga defeat this season -- and a 3-3 draw at Bayern Munich in December.

"Individually, Duesseldorf have a good side, especially in attack, but if we play like we did from the 20th minute against Dortmund, we have a good chance of the three points," said Rangnick.