The former Ajax captain moved to the Bernabeu over a year ago and had a moderately successful first season despite his side's failure to win a trophy as Barcelona collected an historic treble. However, Van der Vaart's prospects of a regular first-team place have dwindled drastically over the summer as president Florentino Perez brought in the likes of Xabi Alonso, Kaka, Cristiano Ronaldo and Esteban Granero.
Rather than seek a transfer to a side which could offer him more playing time, Van der Vaart opted to remain in the Spanish capital. And ahead of tomorrow's friendly with Japan in Enschede, Van Marwijk - whose side are the only European team to qualify for the 2010 finals so far - fears Van der Vaart has left himself with an uphill struggle to nail down a national team place.
The Oranje coach told De Telegraaf: "He has taken a big risk. Though Rafael has had signs he will play, nothing is guaranteed after what went on in pre-season. He's made his choice, but will he even play in his favoured position? At Madrid he is just one more player."
Meanwhile Van Marwijk is relishing the chance to pit his side against a national team from further afield when Japan come to Twente's stadium.
"Playing against one country from another continent is always interesting," he told onsoranje.nl. "Especially since you can face such countries, with their specific playing styles, in a finals tournament. We have already met Tunisia. It is good to have experience of playing such opponents."
Van Marwijk will be without PSV Eindhoven playmaker Ibrahim Afellay, who was replaced by Liverpool winger Ryan Babel earlier this week. Takayuki Morimoto will miss the chance to finally make his Japan debut after a thigh injury forced him out of the squad to face the Netherlands and Ghana. Coach Takeshi Okada will also be without Yoshito Okubo, who is injured.