Chelsea's hopes of offloading controversial figure Diego Costa before the close of the summer transfer window has potentially hit a late stumbling block over the striker's wages.
Costa, who was informed by manager Antonio Conte at the end of last season he would have no future at Stamford Bridge, has been pining for a return to former club Atletico Madrid.
There had been issues over the fee that Atletico would pay to take the Brazilian-born Spain international back - initially wanting to pay only £25m - but a report from the London Evening Standard suggests that two clubs are getting closer to agreement worth closer to the £50m that the Premier League champions had wanted.
That deal would work out at around £41m plus add-ons, but the problem may now come elsewhere. But the Standard's report also notes that Atletico, who remain banned from registering new players until January, are suddenly having doubts about paying Costa's wages while he is unable to play.
For months it had been suggested that Costa, scorer of 52 Premier League goals in three seasons as a Chelsea player, could be sent on loan for the first half of the season until he could be formally registered to play by Atletico midway through the campaign.
Everton are one such club linked with a short-term loan, but Atletico are said to be concerned that clubs could be put off taking Costa until January because of his lack of training after spending the summer in a self-imposed exile in Brazil.
The Spanish transfer window remains open until 1st September, leaving Atletico time to conclude their end of the deal. But with the English, French, German and Italian windows all closing on 31st August, they will lose their opportunity to loan Costa out if they wait.
Alternatively, Atletico could happily wait until January, which would leave Costa as Chelsea's problem for the next four months.