Diego Costa has not been included in Chelsea's 25-man squad for the Champions League group stage, denting his hopes of a reconciliation with boss Antonio Conte.
The Spain international has refused to return to training with the Blues after being informed by Conte at the end of last season that he is no longer wanted.
Having seen a move to Atletico Madrid fall through during the summer, the 28-year-old was offered a lifeline of sorts by the Blues as he was named as part of their 25-man Premier League squad for the 2017-18 campaign.
Costa, currently in self-imposed exile in his native Brazil, will not play a minute of European football before the New Year, however, as he has been omitted from Conte's group-stage squad.
Reports in the British press suggest that Atletico will return with a new bid for Costa in January, at which point they will be free to register new players following the conclusion of their transfer embargo.