Marco Reus has started indoor training but Borussia Dortmund are not certain when the Germany international will play again.
Borussia Dortmund boss Lucien Favre remains unsure when Marco Reus will return from a muscle injury.
Reus was forced off during his side's DFB-Pokal loss to Werder Bremen on February 2, with the Bundesliga club initially announcing he would not return to training again for four weeks.
Favre confirmed on Thursday that while the Germany forward is now working indoors as he continues his recovery, he will not be involved when Dortmund travel to Borussia Monchengladbach on Saturday.
"I can't tell you the exact time when he will return. He started his indoor training yesterday, but that's all I can say about this," Favre told a news conference.
Reus' fitness is a major concern ahead of the Champions League last-16 second leg against Paris Saint-Germain next Wednesday.
They were without their captain for the first meeting at Signal Iduna Park, where Erling Haaland scored twice to secure a 2-1 victory over their French opponents.
With Reus still sidelined, Favre could turn to Mario Gotze ahead of a busy schedule that the Dortmund head coach described as an "English week" during his pre-match press conference.
Gotze has featured sparingly this season, making 13 league appearances, and is out of contract at the end of the season.
Asked if the 2014 World Cup winner may be more heavily involved, Favre replied: "We will see about that. But it is possible, because we are going to have an English week playing on Saturday, Wednesday and again on Saturday.
"It is going really fast and everybody has to prepare for this. We will already see about this tomorrow. He keeps going in the training and performs very well, so everything is possible.
"There are still 10 matches ahead of us in the championship, so everything can happen. Everything happens really fast in football."