Every player with 15 or more scored fours on the Den or LA servers gets a level, shown on their profile. It is a belt, not a rating: it says how much you have been helping your team win lately, and it tells the coach which things are worth your time right now. Different levels work on different things, because the replays say the skill that separates each level from the next is a different one at every step.
Every stat named on this page is explained in plain English on What the numbers mean.