Rennes have reportedly informed Chelsea that they want Blues defender Fikayo Tomori included in a proposed deal for the French club's goalkeeper Edouard Mendy.
Chelsea are believed to be on the verge of securing a deal for Mendy, who is expected to replace Kepa Arrizabalaga as the club's number one goalkeeper this season.
However, according to Telefoot, the details of the agreement are still being finalised, and Rennes have made a last-minute demand to include Tomori in the deal.
Everton have also recently been linked with the centre-back, but Blues boss Frank Lampard said last week that he would not be allowed to leave Stamford Bridge on loan.
The 22-year-old returned to Chelsea last summer after a season on loan with Derby County in the Championship and made 22 appearances in all competitions.
Tomori struggled for action in the latter stages of last term, though, and was left out of the squad that faced Brighton & Hove Albion in the Premier League on Monday night.
