It's not clear exactly what his injury is, but Bruno Martins Indi is off for the Netherlands, and the physios seemed to be taking every precaution with him, putting him in a neck brace before he was strapped down to a stretcher and taken off. He hit the ground hard after a challenge with Tim Cahill, hitting head-first on the pitch, which caused his neck to move in an awkward way.
Hopefully the neck brace was just precautionary, but it looked like a very nasty fall, and there didn't seem to be any consideration about letting him shake off his injury and letting him play on.
The Netherlands have decided to use this as an opportunity to change formations. They started with a back three, but brought on winger Memphis Depay to replace the left central defender, moving Daley Blind to left back. That substitution should shift the Netherlands into a 4-3-3 formation.