Everton boss Ronald Koeman refuses to rule out deal for Chelsea outcast Diego Costa

Costa, 28, has failed to comply with his contract at Chelsea after opting against a return to training.

His time at Stamford Bridge appears to be finished following Antonio Conte’s text, which outlined that the Spain international is no longer part of his plans. 

Conte has already signed Alvaro Morata from Real Madrid for £70m to replace Diego Costa, who wants to re-join Atletico Madrid once their transfer ban is lifted in the New Year.

But Everton boss Koeman has left the door open for a possible deal for Costa after admitting that he would consider a temporary deal despite laughing off Joey Barton's loan claim.

Koeman said ahead of Thursday’s Europa League first-leg playoff against Hajduk Split that will decide who reaches the group phase: “Of course you like to sign players for the future, but if you can get the best one that way, then why not?”

The Everton boss, who completed the club-record £45m signing of Gylfi Sigurdsson from Swansea yesterday, wants to sign another striker. 

Koeman has given up hope of signing Arsenal striker Olivier Giroud and admitted finding a suitable No.9 to fill the void left by Romelu Lukaku is a struggle. 

“It’s difficult ­because it needs to be a quality player, or a young player who can develop or improve.

“We have the possibility maybe to sign good players, but we don’t play in the Champions League – and that sometimes makes things very difficult.

“Still, we need a striker. We signed Sandro, we know about the development of Dominic Calvert-Lewin, but we need ­another one who can play the No.9 role.

“When you play in Europe – and let’s hope we reach the ­Europa League – and in the ­Premier League you can’t do it with one or two strikers.

"If we don’t get a striker, then it’s all about young players.”