The midfielder arrived at Stamford Bridge in the summer for a reported for of €8 million, but has only been afforded 20 minutes of match action for his new club, coming in the Capital One Cup.
Marin began his professional career with Gladbach, winning the 2. Bundesliga in the 2007-08 campaign before rising to prominence with Werder Bremen, and Favre has hinted at a move to bring the former player back to Borussia Park.
"I don't want to comment on this. We'll see in winter," Favre told Bild.
The 23-year old was an integral part of the Bremen squad, and will be eager for increased first-team exposure, but whether a move away from Stamford Bridge is an attraction of Marin remains to be seen.