Chelsea 'have started testing the market for a new shirt sponsor' while negotiating with Yokohama Rubber over extending their existing deal.
The Blues' five-year, £200million deal with the Japanese tyre company comes to an end next year.
Discussions were held between the two parties during Chelsea's pre-season tour of Japan during the summer about extending their partnership.
But, according to The Athletic, Chelsea - with Yokohama's knowledge - have also started testing the market in case a renewal agreement isn't reached.