The wing was the All Blacks' worst injured following their crushing 37-17 victory over France at Eden Park on Saturday night.
Kahui, who injured a hamstring, was one of four players who left the field. No 8 Adam Thomson twisted a knee and ankle, fullback Israel Dagg has a haematoma, and wing Cory Jane has blurred vision following a head knock.
Hansen said today that the selectors would probably rest Kahui as a precaution, which will open the door for wing Zac Guildford, who until Saturday night was destined to go through the World Cup without playing a match.
"Richard Kahui is unfortunately the bloke who probably won't play,'' said Hansen. "Not a serious hamstring but as a precaution we'll probably not pick him. We'll give him the week off and make sure he's dead right.''
No 8 Kieran Read's expected return from an ankle injury will ease the pain if Thomson fails to make the grade.
Read will be looking forward to being involved in the World Cup following the outstanding performances of the loose trio against the France.
Skipper Richie McCaw put in his usually fully committed effort and Jerome Kaino and Thomson also had games to remember, the latter two making their presence felt particularly on defence.
Hansen said the selectors found plenty of positives in the victory. "We got put under pressure for the first 10 minutes of the game and defended well, we were very patient,'' he said.
"We scored four tries off set plays, three off a lineout, one off our own kickoff and of course our scrum was very good. When your set piece is operating really well it gives you a platform to be able to play the game and the backs did particularly well off the back of that platform.''
All Blacks centre Conrad Smith said the team paid special attention to McCaw's milestone after the match.
"It was certainly special in the changing rooms, seeing the effect it had on him,'' he said. "We didn't get too carried away, by the time you finish these games it's about one o'clock and with daylight saving it was a late enough night as it was. Hopefully we can save it for something more important further down the track.''