Celtic legend John Hartson has urged the Bhoys to make sure they lock down Lazio target Dedryck Boyata to a new contract, arguing his World Cup performances could make him worth £40m.
Boyata has been catching the eye with his displays for Belgium at the World Cup and Lazio have been taking an interest in taking him to Serie A this summer.
The centre-back has just a year left on his contract with the Scottish champions and Celtic have been linked with wanting to lock him down on a fresh deal.
Hartson thinks that if Celtic did have Boyata under contract for several more years then they could demand up to £40m for his services given the current state of the transfer market.
The former Celtic striker said on Twitter: "If Boyata had 3/4 years left on a contract and kept playing well at the World Cup in a brilliant team he would be in the 30/40 million category..mark my words.
"This is a very inflated market.
"Not every player is worth what they are transferred for", Hartson added.
Boyata played in all three of Belgium's group stage games at the World Cup, with Roberto Martinez's men having won their group to set up a last 16 meeting with Japan.
