It may seem plausible to you in the context of this idiot's comments. But it is not, in fact, at all plausible. It's an absurd, and implicitly racist, suggestion.
Why jump to assuming it must be his skin tone, and not, say, a natural talent, or a learned and practiced skill, or some clever piece of gritty gamesmanship, that helps him to obscure the football? Hell, the Ravens wore all black uniforms in this very game. Why wouldn't that matter just as much, if not more?
Jumping to the (irrational) conclusion that dark skinned forearms obscure the ball implies that Lamar's success is the result of a "freakish otherness", that he is somehow not the same as "normal" people, and that his success is due to this otherness. This kind of language has been used to discriminate against both American blacks specifically and minorities in general basically since the dawn of media.
Sorry if that's too political for this forum. Couldn't not say it. I don't mean to impune moondog80, who I don't know at all— more responding to Tim Ryan than to you.