Atletico Madrid are trying to re-sign Diego Costa and are expected to make an offer for the Chelsea striker this week, Sky sources understand.
Atletico had agreed a deal to sign Alexandre Lacazette from Lyon this summer but that deal collapsed after their transfer ban was confirmed last month by the Court of Arbitration for Sport.
With Lacazette moving to Arsenal, Atletico are now focusing on buying back Costa.
Despite being Chelsea's top scorer last season, Costa was told last month by manager Antonio Conte that he was not in his plans for next season.
Costa wants to return to Atletico, even though he would not be able to play for them until January.
One option which Atletico have explored is signing Costa and loaning him to a Chinese club until the end of the year. The Chinese midseason window closes on July 14.
Tianijin Quanjian were willing to pay Chelsea £76m for Costa in January, but Atletico believe they can sign him for less than half that figure now.
Atletico sold Costa to Chelsea three years ago for £32m.
Chelsea players return for pre-season training on Monday and fly out for a tour of the Far East on July 18.