The former Manchester United and Real Madrid player, now with Hamburg, failed to make Bert van Marwijk's 23-man selection but remains in the coach's plans.
"I spoke with Ruud and he knows that he is in the picture for the finals in 2012 but that doesn't mean I will invite him for every match," Van Marwijk added.
"But if my opinion changes Ruud will be the first to know."
Van Marwijk had dropped a hint that Van Nistelrooy would be added to the squad because Klaas Jan Huntelaar, who has scored 10 goals in the last six international matches, was struggling to recover from injury.
"Klaas Jan will be in Noordwijk on Monday and then we will see if he is ready for both matches," Van Marwijk said.
Winger Arjen Robben was included in the squad for the first time since the defeat by Spain in last year's World Cup final.
"Robben is one the best strikers of the World so it's obvious I am glad he is back," Van Marwijk, whose side are top of qualifying Group E with four wins from four games.
Van Marwijk added goalkeepers Sander Boschker and Jelle ten Rouwelaar to the squad after first-choice Maarten Stekelenburg of Ajax broke his thumb earlier this week.
The Netherlands are away to Hungary on March 25 before the return in the Amsterdam Arena on March 29.
Squad:
Goalkeepers: Michel Vorm (Utrecht), Sander Boschker (Twente Enschede), Jelle ten Rouwelaar (NAC Breda)
Defenders: Khalid Boulahrouz (VFB Stuttgart), Urby Emanuelson (AC Milan), John Heitinga (Everton), Joris Mathijsen (Hamburg SV), Erik Pieters (PSV Eindhoven), Ron Vlaar (Feyenoord), Gregory van der Wiel (Ajax Amsterdam)
Midfielders: Ibrahim Afellay (Barcelona), Mark van Bommel (AC Milan), Theo Janssen (Twente Enschede), Nigel de Jong (Manchester City), Hedwiges Maduro (Valencia), Wesley Sneijder (Inter Milan), Kevin Strootman (Utrecht), Rafael van der Vaart (Tottenham Hotspur).
Forwards: Eljero Elia (Hamburg SV), Klaas Jan Huntelaar (Schalke O4), Dirk Kuyt (Liverpool), Robin van Persie (Arsenal), Arjen Robben (Bayern Munich).
