Diego Costa has been told he has no future at Chelsea

Everton manager Ronald Koeman has admitted he would be open to signing Chelsea forward Diego Costa on loan.

Costa is surplus to requirements at Chelsea, but has been told he must return to training despite having no future at Stamford Bridge.

The 28-year-old, who is currently in Brazil, released a statement on Thursday insisting he will not return to Chelsea and that he must return to former club Atletico Madrid.

Costa scored 20 goals last season as Chelsea won the Premier League title under Antonio Conte

Atletico are unable to register any new players this summer having had their appeal against their transfer ban rejected by the Court of Arbitration for Sport (CAS) in June, meaning Costa would not be able to feature until January if he did complete a move back to the club.

Having secured the £45m club-record signing of midfielder Gylfi Sigurdsson on Wednesday, Koeman has set his sights on adding another striker to his squad and hinted at a possible move for Costa.

When asked whether further signings would be "permanent or temporary", Koeman said: "Is this about Costa?

Ronald Koeman is looking to add another striker to his squad before the end of the summer transfer window

"Of course you like to sign players for the future, but if you can get the best one that way, then why not?"

"That's for six months, the season, two years.

"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."