Per Josh Katzenstein of the Detroit News, here's referee Pete Morelli's explanation of why Cowboys linebacker Anthony Hitchens wasn't called for defensive pass interference on Brandon Pettigrew today. According to Morelli, the back judge thought it was DPI, but the head linesman determined that Hitchens was face-guarding.
Face-guarding is intentionally blocking the view of a player, and as Morelli says, it's legal as long as there's no contact. Was Hitchens actually face-guarding in that instance, however? Watch the play for yourself: