Stoke City manager Mark Hughes believes on-loan Kurt Zouma is worth up £40m ($54m) as he praised the centre-back's impact at the bet365 Stadium.
Zouma, 22, joined Stoke on a season-long loan from Chelsea in July, with the Potters paying a £7m loan fee.
Hughes said the loan fee Stoke had to pay was a bargain given the quality offered by the France international, and added that it was only way for the Potters to bring in players of his quality to the bet365 Stadium.
"Kurt Zouma is a £30-40m centre-half. We can't afford that, but in the loan market we can get him here so that's a good thing," he was quoted as saying by the Daily Mirror.
"We have to do that because we're not going to go into the market for a £60million player."
Zouma signed a six-year contract at Chelsea before joining Stoke on loan, with Hughes saying that a desire to play in the World Cup for France next summer motivated the defender to join the Potters for the season.
"It coincides with the World Cup, so wanting to play week-in, week-out would have been in his thinking," the Stoke boss said.
"At one point I think he felt he needed to leave Chelsea because he wanted to play regularly but the contract he was offered tied him to them."
Hughes backed Zouma to be future regular in Chelsea's defence and said he would try to extend the Frenchman's loan deal into next season.
"We'd be more than happy to pursue it if the potential to do it was there – we'd certainly ask," he said.
"They sent Andreas Christiansen to Germany and now he's playing in Chelsea's team," he added. "I suspect that's what will happen with Kurt."
Stoke, who are on a five-game winless run in all competitions, host Southampton at the bet365 Stadium on 30 September.