According to reports in Spain, Atletico Madrid's deal to sign Costa from Chelsea should be 'closed this week'.
Spanish newspaper 'Marca' reported that on Monday, the two clubs were negotiating a fee of €60m (£54m) for the wantaway Spanish international striker.
However, Atletico, who can't officially register any new players until January due to a transfer ban, are yet to agree with Chelsea on how much will be paid up front and what sum will be paid in bonuses.
'Marca' claim that Chelsea became more willing to negotiate after Costa insisted that he would not return to the club until his future had been sorted out.
The 28-year-old has not played for Chelsea since the FA cup final defeat to Arsenal at the end of May after Costa was reportedly sent a text by Antonio Conte telling him he was no longer part of his plans.