Mauricio Pochettino has sought to reassure the Tottenham Hotspur support over the future of Toby Alderweireld, urging them to stay calm and put their trust in the chairman, Daniel Levy.

Alderweireld’s contract contains a one-year extension option, which is scheduled to activate in the summer of 2019 and would see him contracted until 2020. But it also features a £25m release clause. In the summer of 2019, the central defender would be permitted to leave if a rival club were to pay £25m and complete the transfer at least 14 days before the closure of the window.

The 28-year-old earns a basic wage of £50,000 a week at Tottenham and he wants a substantial rise in what could well be his last major contract. Pochettino said in December 2016 that negotiations over a new deal had started but there has yet to be a breakthrough.

The release clause has made some fans edgy but Pochettino fails to see why. The manager made the point that Lionel Messi only signed his Barcelona contract at the end of November to replace a deal that was set to expire in the summer of 2018.

“This is a message for our fans and for everyone: Toby still has two-and-a-half years of contract,” Pochettino said. “Messi was six months left on his contract. Messi! If something happens [on Alderweireld], the club is going to communicate. But I don’t understand all these things when the players are all under contract.”

It was put to Pochettino the release clause meant Tottenham were sure of keeping Alderweireld for only another 18 months. “It’s two and a half years,” Pochettino replied. “Daniel Levy said to me: ‘Don’t worry, gaffer. It’s two and a half years.’

“Players like Érik Lamela still haven’t signed [new contracts]. Or another player signs with two years left. It’s different contexts, different reasons. It’s not only to say the club needs to do this and this. Calm. Calm, our fans. Because Daniel is very good. He has managed the club for 17 or 18 years. Look at how Tottenham was 18 years ago and how it is today. I think full credit to Daniel. Let him work. It is important the fans trust in Daniel.”

Alderweireld has been out since 1 November with a hamstring injury. He is expected to return in late January or early February.