The 31-year-old has been linked with several clubs recently, including Inter Milan.
“I am available for a club who wishes to have me,” the centre-half said.
“But before being approached, an agreement must be found with Chelsea, although I am delighted that several clubs are interested in me.
“I have had four extraordinary years at Chelsea till this year, which has not been very good, indeed the worst of my career. I wasn’t in great shape because I haven’t played.
“But if there is no transfer, I will be fine at Chelsea.”