Chelsea manager Antonio Conte decided not to keep Diego Costa in his squad for next season in November.
Metro claims that the Italian was upset after the Spaniard posted a photo on Instagram with Atletico Madrid boss Diego Pablo Simeone.
It seems Conte interpreted the photo as more proof that the 28-year-old was desperate to leave Stamford Bridge to make a return to the Spanish Liga.
On Thursday, Costa announced that he will no longer play for Chelsea after receiving an SMS message from his manager.
"I'm a Chelsea player, but they do not want me there," Costa is quoted as saying by the BBC.
"Antonio Conte has told me by message that I do not follow at Chelsea and that's it. Conte said he did not count on me for next season.
"My relationship with the coach has been bad this season. It's a shame, I've already forwarded the message to Chelsea people to decide."
