The chances of Diego Costa rejoining Atletico Madrid from Chelsea before the closure of the Spanish transfer window are reportedly "unlikely, but not impossible".

The two clubs have until midnight on Friday to reach an agreement over a transfer fee for the Spain international, who has been in self-imposed exile in Brazil for the past two months.

Costa has made it clear that he wants to rejoin Atletico after being told he is not in Antonio Conte's Chelsea plans for the season, although Los Colchoneros are under embargo at present.

According to Sky Sports News, which quotes a source close to the negotiations, the chances of a last-minute deal being struck are becoming "improbable, but in football nothing is impossible".

One option being actively pursued is finding a club for Costa to join on loan until January, when Atletico can register the player and utilise him in matches.

Costa has won two Premier League titles in three years since joining Chelsea from Atletico for £32m in 2014.