The two clashed heads and lay on the pitch for some time before Smalling left the field on a stretcher while Hutelaar managed to walk off but holding a bandage to his head.
Dutch coach Bert van Marwijk told reporters: "Huntelaar has gone to hospital because we think he has some damage there (to his head) but we don't know for sure.
"He looked better in the dressing room than on the pitch, but we have decided to have him checked out."
England's interim coach Stuart Pearce said Manchester United defender Smalling was also attending hospital for a check-up.
"Chris went to hospital. I spoke with him and he was conscious, but he split his head open. Our thoughts are with him and I am hoping that he will be fine."