if you pass a lot on a team that teams run game will look more stout than it really is. They can be ranked that high on run D simply because no one is running on them because the pass game is so easy....Passing a lot will also allow a good bit of time for Goff to make his play.....A passing game uses less time than a run game does.
Have they played a game with a 2-1 split run to pass before? They also have scored a lot of points this year, fall behind and the run games dwindles that may also have a hand in their rank vs. the run?