The 19 year-old impressed in recent trials and RKC hope to sign him in January.
RKC chief scout Janus van Gelder admits they do not have the resources to sign Troost-Ekong outright, but hope to take him on-loan.
"We would have liked to have William. But it does depend on Tottenham. We do not have the means to sign him permanently in the winter," he told Voetbal International.
"It would be better for his development if he has minutes of play. It remains to be seen how the situation develops."