Van der Vaart sat out the recent wins over Turkey and Hungary after suffering a disrupted pre-season due to his move from Tottenham Hotspur to Hamburg.
But he, along with fellow established internationals Nigel de Jong and Ibrahim Afellay, have been included for the double-header later this month.
De Jong and Afellay were also transferred late in the transfer window, the former from Manchester City to AC Milan and the latter from Barcelona to Schalke on loan.
But it is Van der Vaart's return which is likely to be the most important, with the former Real Madrid man expected to go straight into the side to replace the injured Wesley Sneijder.
"We concluded he is incredibly fit and that's good news because I already knew he is a great footballer,'' Van Gaal said.
There were two new faces in Van Gaal's 20-man party - Ajax goalkeeper Kenneth Vermeer and Feyenoord forward Ruben Schaken. The Dutch play Andorra in Rotterdam next Friday before visiting Romania four days later.
Although they were not named in the initial party, Van Gaal is hoping Feyenoord defender Joris Mathijsen and Bayern Munich winger Arjen Robben will be fit for the latter assignment in Bucharest. "I hope and expect Mathijsen will play, Robben is more difficult,'' Van Gaal said.
Goalkeepers: Maarten Stekelenburg (Roma), Michel Vorm (Swansea City), Kenneth Vermeer (Ajax)
Defenders: John Heitinga (Everton), Daryl Janmaat (Feyenoord), Bruno Martins Indi (Feyenoord), Nick Viergever (AZ Alkmaar), Ron Vlaar (Aston Villa), Ricardo Van Rhijn (Ajax)
Midfielders: Urby Emanuelson (AC Milan), Nigel De Jong (AC Milan), Kevin Strootman (PSV Eindhoven), Rafael Van der Vaart (Hamburg), Ibrahim Afellay (Schalke)
Forwards: Klaas-Jan Huntelaar (Schalke), Jeremain Lens (PSV Eindhoven), Luciano Narsingh (PSV Eindhoven), Robin Van Persie (Manchester United), Dirk Kuyt (Fenerbahce), Ruben Schaken (Feyenoord)