Kane signed a six-year contract in June before winning the Golden Boot at the World Cup, where he scored six goals in England's run to the semi-finals.
There has been no slow down for Kane this season, as he's already bagged nine goals in the English top flight, while adding another four in the Champions League.
The striker has shown little interest in leaving the Premier League club but reports have linked him to both Real Madrid and Barca in the past, with some suggesting the La Liga champions see him as a possible long-term successor to Luis Suarez.
The Spurs star will have a chance to impress Barca's board at close quarters on Tuesday when Tottenham visit in the Champions League, with Spurs needing a result better than Inter's against PSV in order to advance to the knockout stages.
But while Valverde is impressed with the development of the 25-year-old, he would give no clues as to whether Barca would be interested in a deal.
"He's a great, extraordinary forward on a global level," Valverde told a news conference. "He can shoot, he is good in the air and makes the difference in the box. You can't give him any space, even one metre. He is a difference-maker."
Valverde pointed out he dislikes discussing players from other clubs, yet added he is respectful of the talent and production Kane brings to the table.
"I don't like talking about players from other teams, we try to have some discretion about them and worry about our own, but that doesn't mean we can't have respect for what he does."
Barcelona have already advanced to the knockout stage of the Champions League and cliched the top spot in Group B.
As a result, Valverde has already confirmed Suarez will miss Tuesday's contest, though he was coy on Lionel Messi's involvement.