According to Spanish media outlet Marca, La Liga side Atletico Madrid are desperate to re-sign Diego Costa and are prepared to pay a record fee of £57million.
The potential deal would include an estimated £48million upfront with a further £9million in bonus add-ons.
While confirming Marca’s claim of a final offer from Atletico Madrid, La Liga expert Guillem Balague revealed Chelsea are only willing to sell Costa for £66million.
“Atleti have made one last offer. It’s €55m (£48m) plus €10m (£8.8m) in bonuses,” Balague told Sky Sports.
“They say it’s a final offer but that doesn’t mean much at all.
“If Chelsea reject it they will have to find another €10m (£8.8m), which is about the difference in valuation between Chelsea and Atleti at the moment.”
Costa’s reluctance to return to Chelsea is reportedly making Chelsea play hardball over his potential move back to Spain, despite boss Antonio Conte admitting his does not see Costa as a player he can trust.