The 23-year-old joined the Blues in a £7million deal from Werder Bremen in the summer, but has yet to feature in the Premier League so far this season.
With fierce competition for places at Stamford Bridge, particularly in midfield, Roberto Di Matteo faces the daunting task of keeping all his players happy, while juggling his squad to cope with the demands of both domestic and European football.
The Champions League holders will attempt to become the first club to retain the trophy, with Russian owner Roman Abramovich insisting that the competition remains a top priority this season, in addition to a renewed tilt at the Premier League title.
With that in mind, Marin will likely feature in Chelsea's long-term plans, but the German star might not want to wait around, as he looks to kickstart his international career, with regular football an absolute necessity if he is to do so.
Gladbach coach, Lucien Favre, is ready to offer the midfielder that opportunity, to return to the club where he started his career, and incidentally, won his first German cap, before moving on to Bremen in 2009.
"A player like Marin could be a good fit for us," Favre was quoted in the Sunday Mirror. "We will have to see what happens in the winter break but we have got nine games to go until then, so I don't want to say more."