The 34-year-old was said to be considering the deal, and he has now disclosed that the role on offer differs from his current position and requires careful consideration.
Thanks to everyone for the kind wishes. The contract extension the club has offered me is a different role and I hope everyone will understand I want to take the time to consider it carefully before making a decision, Terry wrote in an Instagram post.
In April, outgoing manager Guus Hiddink stated he had been giving the Chelsea captain work experience during his spell on the sidelines with an Achilles problem.
Terry has been involved in four Premier League title triumphs, five FA Cup wins and Champions League glory in 2011-12.
Despite reported interest from across the globe, the centre-back has expressed his desire to remain at Chelsea.
