Andreas Christensen has entered the final six months of his contract.
The Dane is expected to leave Stamford Bridge by the end of this season with Bayern Munich and Borussia Dortmund as potential candidates to sign the defender.
Both Antonio Rudiger and Cesar Azpilicueta will also depart in the summer and Chelsea are keen to extend either of these players’ deals.
Chelsea legend Gianfranco Zola believes Christensen and either of Rudiger and Azplicueta will stay beyond the summer.
Zola said to The Sun: “We are talking about two of them being key players and have been very successful at the club. Right now, they are playing all the time — that is Rudiger and Azpilicueta.
“The third one (Christensen) hasn’t played as much but is the youngest. You don’t want to lose players when they have been so good like Azpilicueta and Rudiger.
“At the same time, you don’t want to lose a good prospect like Christensen.
“I think we will see two stay — but don’t ask me the names. Luckily, I am not Tuchel and it is very easy for me not to answer the question. I would maybe keep the young one and one other.”