Denmark international Christensen has spent the past two seasons on loan at Gladbach, but is returning to Chelsea to push for a regular first-team spot this summer.
With current Blues captain John Terry leaving Stamford Bridge, Christensen is widely expected to figure prominently in manager Antonio Conte’s pre-season preparations.
However, if things do not go to plan for Christensen, then Gladbach’s sporting director Max Eberl would be keen to re-sign the centre-half, either on loan or permanently.
“We will lose him, because he has to return,” Eberl told Kicker. “This is certain.
“But, if he does pre-season at Chelsea and then does not play the role that he hopes to, we have the chance to talk again as a club where he has gained two years’ good experience.
“It could also be that he plays. Or it may be the case that they want to sell him for €25 million, then we would be out of the race.
“But there are still these opportunities, because Andreas is incredibly comfortable in Gladbach and he, I think, would like to stay in Gladbach.
“He would also like to be a regular in Chelsea’s starting XI, but they have just become champions who will play in the Champions League and will also want to achieve something next season.
“In any case, Andreas feels very comfortable in Gladbach.”