Celtic keeper Craig Gordon wants to hold talks with Chelsea over a move to Stamford Bridge.
The Premier League leaders contacted the Scottish champions with an offer to purchase the Scotland international on Thursday morning.
Offering a fee in the region of £2.5million, Chelsea were told the 34-year-old is not for sale.
Keen to secure a replacement for Asmir Begovic before selling the Bosnian international to Bournemouth for £10million, however, the London club are now assessing their options.