Ronald Koeman has said he would welcome the chance to bring Diego Costa to Everton as he reiterated his desire to sign a striker before the transfer deadline.

Costa is in exile in Brazil having refused to return to training with Chelsea and stated his intention to return to his former club Atlético Madrid. A late diversion to Goodison Park may be a remote prospect but Koeman, who wants to add experience to the Everton attack, said on Friday he would be interested in the Spain international.

Asked about the possibility of luring the 28-year-old back from Brazil, the Everton manager replied: “I have always said there will be a warm welcome for every good player here and he is a good player.”

Koeman intends to discuss late transfer targets with the Everton board after Sunday’s visit to Stamford Bridge, the squad’s third demanding away trip of the week. Despite Dominic Calvert-Lewin’s impressive start to the campaign the Everton manager insists he cannot be reliant on the England Under-20 World Cup winner, and the summer signing Sandro Ramírez, as his frontline options for the whole season.

“We are still looking to bring in a striker,” he said. “It is not about being unhappy with Dominic – I am very happy with him – but he is still young and we need more competition up front. We have tough fixtures and a lot of international players and a lot of players selected for the under-21s – six Everton players with England. For young players the most difficult thing is being regular with their performances but Dominic, like Tom Davies, is doing exceptionally well.”

Koeman believes Jordan Pickford is on course to become England’s first-choice goalkeeper and justify Everton’s £30m outlay after only four appearances for the Merseyside club.

Pickford, who became the most expensive British goalkeeper in history when he moved from Sunderland this summer, continued a highly impressive start to his Everton career when saving a penalty against Hajduk Split in the Europa League play-off on Thursday. His contribution followed a call-up to the senior England squad for next month’s World Cup qualifiers against Malta and Slovakia, and Koeman believes it is only a question of time before the 23-year-old establishes himself as No1 for club and country.

Koeman said: “Jordan is really strong. From the beginning he has been really comfortable, he has not looked nervous and he gets the confidence of being the No1. The reason we signed him for big money was that we expect him to be the No1 in the future for England. That is the confidence we have in the boy and so far he is doing fantastic. Now it is about keeping that level because it is always more difficult to keep it than to get there.”

Pickford has played 14 times for England Under-21s and was selected by Gareth Southgate for last season’s senior games against Slovenia, Scotland and Spain, but has yet to make his full senior debut. Koeman believes it was evidence of the keeper’s “good personality” that he was unafraid to berate Wayne Rooney over a mistake he made against Hajduk. “Criticism with respect is good,” he said.

Koeman added: “It is easy for a goalkeeper to stop 100 balls than if you get one or two in a game, because then you need to be focused for that one moment. It was like that in Split. The penalty was a really important moment. If he doesn’t save the penalty it is 2-1 and with the atmosphere in the stadium it could have been really tough for the last 30 minutes. But after he made the save it was over. Everybody likes that kind of goalkeeper.

“You look to their stats and he had, even while being relegated with Sunderland, a good season. That is difficult because they conceded a lot of goals but in our view he was still that promising goalkeeper for the future of Everton. That was the reason we paid that money for him. We think he will be the best in the future and he is on a good way.”