Chelsea are holding out for a transfer fee of £44m ($57m) for Diego Costa, who is keen on a return to former club Atletico Madrid.

The Independent says the Blues will let Costa leave Stamford Bridge after they agreed a deal to sign Alvaro Morata from Real Madrid for around £60m.

Atletico had been hoping to sign Costa for a cut-price of £25m in the knowledge that Chelsea boss Antonio Conte is keen to sell him, but the Premier League champions have so far refused to budge on their valuation of the Spain international.

Costa, 28, has two years left on his contract at Stamford Bridge.

Conte informed the forward via text message last month that he was no longer part of his plans, with the club's hierarchy fearing that the move had wiped out millions off the striker's market value.

Atletico coach Diego Simeone remains determined to land Costa, even though the La Liga side are unable to register any new players until January due to a transfer ban.

Costa admitted last month that he was interested in rejoining Atletico, but expressed concerns over potentially missing half a season of football ahead of the 2018 World Cup in Russia.

"Conte has sent a message saying that he does not want me. If they don't want me there, I'll have to search for a team," Costa was reported as saying by the Daily Mirror.

Diego Costa and Antonio Conte
Diego Costa's relationship with Chelsea boss Antonio Conte has broken down Getty Images

"To go to Atleti would be nice but I have to think about it. This is a World Cup year and I cannot be not playing for three or four months."

Atletico president Enrique Cerezo played down talk of an imminent move for Costa, who is currently on holiday in Brazil.

"Costa is a Chelsea player at the moment, and you know for a long time now that we cannot sign anyone [this summer]," he was reported as saying by ESPN on 18 July.

"It is a long time since I spoke with him. At least a year, since he left here. I have seen him with the national team, but spoken to him very little."