THE Newcastle Knights believe skipper Kalyn Ponga should have been allowed to play in Friday's clash with Gold Coast Titans and have queried the consistency of the NRL's concussion protocols.

The Queensland fullback was ordered from the field after being hit high by NSW halfback Nathan Cleary 10 minutes from full-time in Origin II on Sunday, after the NRL's bunker-based independent doctor ruled he had suffered a category-one concussion, based on vision of the incident.