Netherlands' Vincent Janssen in action with England's John Stones
Now courtesy of newspaper De Telegraaf, details of Tottenham's offer have emerged.
Netherland's Vincent Janssen celebrates
It is claimed Tottenham bid 14 million Euros for Janssen, offering to spread the payment in instalments over a three-year period.
This was deemed unacceptable to AZ Alkmaar, and the paper claim a previous offer of 12.5 million Euros plus 2.5m in bonuses as also rejected.
Athletic Bilbao's Carlos Gurpegi in action against AZ Alkmaar's Vincent Janssen
The report states AZ are holding out for a fee of 20 million Euros for the Dutch international striker, who finished as top scorer in the Eredivisie last season.
It is claimed Janssen is keen on a move, wanting to get started with the next step of his career as soon as possible.
Vincent Janssen scores the first goal for the Netherlands from the penalty spot