Benfica have told Chelsea that they will need to pay £38million for former player Nemanja Matic, according to the Daily Star.
The Serbian playmaker signed for Chelsea in 2010, but made just three appearances before being used as a makeweight in a deal to bring David Luiz to Stamford Bridge six months later.
He was one of the stand players for Benfica in a season which saw them reach the Europa League final, which they lost to Chelsea in Amsterdam last month.
Meanwhile, Borussia Dortmund sporting director Michael Zorc has claimed that Blues midfielder Kevin De Bruyne is keen on joining the German club, Sky Sports understands.
The 21 year old, who recently returned from a season long loan with Werder Bremen, was also recently linked with a move to fellow Bundesliga side Bayer Leverkusen as part of the deal which saw Andre Schurrle move to Stamford Bridge.
However, Zorc believes that it is the players wish to join the Champions League runners up.
The Belgian international is yet to make an appearance for the Blues, having signed from Genk last July.
Elsewhere, the club appear to have won the race to sign Bristol City’s highly rated teenager Jacob Maddox.
The 14 year old is said to have agreed a four year deal with Chelsea, who will pay City a compensation fee for his services.