Borussia Monchengladbach coach Lucien Favre has remained coy on the possibility of signing winger Marko Marin from Chelsea.
The 23-year-old moved to the Premier League club from Werder Bremen in the summer but has struggled for playing time so far for Roberto Di Matteo's side.
"I don't want to comment on this," Favre told Bild. "We'll see in winter."
Marin played for Monchengladbach between 2007 and 2009.