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.
Their agreement was the second biggest in the Premier League when it was announced back in 2015, with only Manchester United's £53m-a-year tie-up with Chevrolet more lucrative in the top flight.
Since then, Arsenal, Liverpool and Tottenham Hotspur have also agreed £40m-a-year shirt sponsorship deals, By reaching out to other companies, it is possible that Chelsea feel they can improve on that sum.
In 2016, Chelsea signed the largest commercial deal in their history with Nike, worth £60m-a-season over 15 years.
Chelsea remain an attractive proposition for any prospective shirt sponsor despite failing to challenge for the Premier League title over the past two seasons.
They did win the Europa League title back in May, returning them to the Champions League for this season.