After his year out following a head knock last season, Ngatai missed the match against the Crusaders in Fiji last Friday after reporting a headache post-training on the Monday. The team played it safe and kept him from travelling with the squad overseas the following day.
Chiefs coach Dave Rennie said while Ngatai was on the improve, he was unlikely to play a part at Eden Park.
"Charlie's pretty good," he said. "He's had about four days symptom-free. But we're unlikely to use him this week. We want to be really sure.