The incensed striker was abandoned by the Blues boss Antonio Conte at the end of last season by using a text message to express his feelings that he is no longer needed and he is not in his plan any more.
But the Spain International viewed it as an incorrigible act after he was let down by the Italian man.
Costa geared up to return to Atletico Madrid after saying he was treated like a criminal.
He has won two EPL with the club since joining from Aletico, and also contributed in major competition for the club.
Earlier before closing the summer transfer window Atletico ortdered Diego Costa to make peace with the club before they consider buying him for just [£25m], while Conte want [£50m].
He was under pressure to return to England to solve the issue between him and the club but refuses to bow to the club.
Costa was called back by the Blues to turn up following their preparation for the new season and he is included in the club 25-man Premier League squad, but after the submission of Champion League list shapilo sports notice that Diego Costa is not among.
