Maduro, 26, sustained an ankle injury in the training-ground collision with FC Twente forward De Jong.
Describing the incident, Maduro told www.telegraaf.nl: "He (De Jong) could not help it, it was pure (bad) luck.
"It was an unfortunate duel with Luuk. He wanted to get the ball, but I was faster and this left my left ankle hooked between his legs. I felt the joint make a double 'clap', so I'm worried that there is damage, but hopefully not that bad."
Maduro, who offers
Van Marwijk has drafted in Feyenoord defender
UEFA president Michel Platini said preparations for Euro 2016 were "progressing well" after a meeting of the organising committee in Lille.