Chelsea insisted upon a buy-back option in their deal with Lyon for Bertrand Traore.

The striker was sold by Chelsea to OL in the summer of 2017 for €10m.

And Mediacities says Chelsea have a buy-back option which can be triggered to the tune of €17.5m.

The clause is valid between June 10 and July 10 2019 plus between June 10 and July 10, 2020.

Interestingly, while he is currently on €320,000-a-month, Traore can earn a monthly bonus of €30,000 if he adheres to OL's 'rules and ethics' guidelines.