Reports in Holland and Germany suggest the Tottenham playmaker could be on his way out of White Hart Lane once the transfer winder re-opens.
The Dutch playmaker has spent the last two seasons with Spurs, but saw them miss out on UEFA Champions League qualification in 2011/12 as a result of Chelsea's success in the competition.
It is now being suggested that he would be willing to discuss a possible return to German football.
Van der Vaart spent three productive years with Hamburg between 2005 and 2008, before moving on to Real Madrid.
Schalke are keen to bring him back to the Bundesliga, allowing him to link up with international colleague Klaas-Jan Huntelaar.
Van der Vaart is reluctant to discuss his future, though, with a shot at Euro 2012 glory with Holland dominating his thoughts at present.
"I won't say anything about it," he told De Telegraaf.
"At the moment I am fully focused on Euro 2012."