Costa has complained about his treatment under Conte, who has fined him for not returning from his summer break

Chelsea have edged close to an agreement to sell Diego Costa to Atletico Madrid in a deal worth up to £50 million.

The clubs have discussed an initial fee of about £40 million with the rest in add-ons for the striker who has not returned to the west London club this season. Atletico can sign the player but can not register him until January because of a transfer ban that was imposed by Fifa this summer.

Enrique Cerezo, the Atletico Madrid president, has said that he is “optimistic” Costa will join. The Spanish transfer window will close on Friday meaning that the deal could take place after English clubs are permitted to bring in players. The English window closes tomorrow night at 11pm.

Costa has