Although the clips that attach Newton's clear visor to the helmet are small and difficult to see, the league considers it a violation of its equipment policy.
NFL rules state that "No visible identification of a manufacturer's name or logo on the exterior of a helmet or on any attachment to a helmet is permitted unless provided for under a commercial arrangement between the League and manufacturer."
Nike has a signed contract to be the NFL's equipment provider. Newton is one of Under Armour's main clients.
The violation was first pointed in an article Tuesday by Forbes.com.
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