The Belgium defender reported for preseason training at Ajax yesterday.
Vertonghen told the club's official website: "Of course it goes through my head that there is still no clarity about my future.
"It is difficult and I can't say I don't think about it but that's how it is and I have to adapt. For now I play for Ajax and I will always give 100% for them.
"I am a professional athlete and despite all the issues for me it is simply the beginning of a new season. And that, for me, starts at Ajax."
Vertonghen is hoping the situation is resolved as soon as possible.
He added: "It is obviously impossible to say how long these things take but well before August 31 (the closing of the transfer window) there must be clarity.
"Until then I will just focus on Ajax."