OPRK means Opponent Ranking. For example, if there are 2 players from the Tampa Bay Buccaneers there’d be a green and a red one. Of course, red means ‘bad’ and green means ‘good’. Mike Williams’ OPRK is green because of Atlanta’s past defense. PVO stands for Position vs. Opponent and determines the way your player will go against a defense. So if the defense doesn’t do very well their PVO will be negative.