Chelsea will allow Tiemoue Bakayoko to join AC Milan on a permanent basis if the Italian club gives them Ivorian midfielder Franck Kessie in exchange.
Bakayoko failed to make a positive impression in the Premier League after his £40m move from Monaco in 2017 and was shipped out on loan to Milan last summer.
He has rediscovered his best form at the San Siro and Milan want to make the move permanent. They have a €35m purchase option, but that may be difficult because of Financial Fair Play restrictions.
Kessie is currently on a two-year loan from Serie A rivals Atalanta, but Milan are obliged to make his move permanent at the end of the season.
They would not be keen to part with the 22-year-old, who has played every league match for which he has been eligible over the last two seasons, and is playing a key role this season in trying to get Milan back into the Champions League.
They have not competed in the Champions League since 2013/14, but currently sit fourth in Serie A after a six-match unbeaten run.
Qualification for the Champions League, and the financial rewards that it brings, might help Milan to get a deal done for Bakayoko without the need to sell Kessie.
Chelsea boss Maurizio Sarri is keen to add to his midfield options after a frustrating January which saw the Blues lose Cesc Fabregas with no replacement coming in.