Atletico Madrid are said to be "confident" of completing a deal for Chelsea striker Diego Costa "within the next few days".
The La Liga giants have been repeatedly linked with re-signing the 27-year-old, who moved to the Blues two years ago after they met the £32m release clause in his Atletico contract.
Chelsea are not keen to see the Spaniard depart Stamford Bridge although new manager Antonio Conte has admitted that he could leave this summer.
According to The Sun, Diego Simeone's side are tabling a bid in the region of £40m and hope to get the deal over the line sooner rather than later.
Costa fuelled rumours of a return to the Vicente Calderon earlier this week by posting a "thank you" message to his Chelsea teammates on Instagram.