The 18-year-old (pictured, left) will fly to France, where he recently joined Le Mans, for treatment on a broken left fibia sustained in Monday's Group A game against co-hosts Gabon.
Amadou, better known by his nickname Kalala, had just come on as a 63rd-minute substitute in Libreville when he was caught by a tackle from Gabon's Stephane Nguema.
He attempted to play on but had to be carried off on a stretcher, leaving Niger, who had already made three substitutions, to play the last quarter of an hour with 10 men.
Gabon won the match 2-0.
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