The 28-year-old's future at the Premier League club was plunged into doubt in January after a stunning offer from the Chinese Super League.
Costa was dropped for one game in January by boss Antonio Conte amid reports of a bust-up between the pair over the reported interest from the Far East.
He returned to the team and has continued to impress, taking his tally to 16 goals this season to help Chelsea move ten points clear at the to of the Premier League.
But, according to The Sun, there is a real possibility Costa could move on in the summer.