Diego Costa has been homesick in England and has made contract with Atletico Madrid about a return this summer.

Costa joined Chelsea last summer on a £32 million transfer from Atleti.

Jose Mourinho says "he's the happiest guy in the dressing room, so if this is unhappiness, I'm happy with that."

Costa continued to have hamstring injuries this season and did not complete a full 90 minutes past mid-March.

The 26-year-old split with his girlfriend after swapping Spain for England and has struggled with the language.

Chelsea are likely to be in regular contact with Atlético this summer as they weigh up a £43 million move for the France international forward Antoine Griezmann, a fee which would trigger the buy-out clause in his deal