Atletico Madrid have included Sergio Aguero in their squad for their Champions League qualifier against Panathinaikos.
The Sun says Chelsea have 24 hours to meet Aguero's £50million get-out clause at Atletico Madrid.
The Argie star is set to face Panathinaikos in tomorrow's Champions League qualifier unless the Blues increase their £42m bid.
If Aguero plays, he will be cup-tied for Chelsea's own European campaign this season - scuppering the deal.