If I am not mistaken - somebody correct me if I am wrong - the injury report was updated a few years ago to strictly correlate with the percentage chances of someone playing in the game, and nothing else, since the terms were ambiguous. Specifically, probable equated to 75% or more chance of playing, questionable meant 50%, doubtful meant 25% and out meant zero %. At that point it no longer had anything to do with a player being bruised, slowed down, hurt, or 'injured.'
In other words, if a team was sure somebody would play (e.g., Maroney), then there was no reason to list him on an injury report that was instituted a half century ago due to gambling.
If anybody has a problem with the Pats' injury report, it should be for Brady's weekly listing as probable; there was nothing improper with Maroney's non-listing as per the NFL rules.