The Denmark international is being linked with a number of European sides regarding a potential January move and his former Ajax teammate has given a glowing appraisal of the 20-year olds potential.
"Technically he's one of the best players I've played with," Vertonghen told the Evening Standard. "He's right-footed and left-footed and he's always fit.
"Since he was 17 or 18 years old he's played every game for Ajax, he's never been injured, and I think when he gains a bit more physical strength then he can play in every team.
"I don't want to talk for him but he's a good player, and I think a good player can play here."