Trevor Siemian's passer rating this past Sunday was 30.5. Between 2004 and 2016, 3,328 regular season games were played in the NFL. 221 of them (6.6%) involved a passer rating of 33 or less by one of the two teams involved. This is a fairly rare event in the league. 19 of those 221 games in which a team had a QB with a passer rating of 33 or less resulted in a win. 202 of the 221 games resulted in losses. In other words, if a team has a QB with a passer rating of 33 or less in a game, it has a 0.6% chance of winning that game. Six wins out of a thousand tries, in games of that nature. In the 19 wins by teams with passer ratings of 33 or lower, the opponents' passer ratings in those games averaged 54. The average margin of victory by those 19 teams was 7.5 points. In the 202 losses by teams with passer ratings of 33 or lower, the opponents' passer ratings in those games averaged 88.7, which is not significantly different from the league average. The average margin of defeat for those 202 teams was 19.8 points, which is an uncommon margin of defeat in the league. 45 of those losses (22.3%, or more than 1 in every 5 games) were by 26 points or more, as in the Broncos loss by 26 to the Dolphins Sunday. In other words, a team stands to win a game -- and not by much -- with a passer rating of 33 or less only when the opposing team's passer rating isn't much higher, whereas it's very likely to lose a game -- by a whole lot -- when the opposing team has only an average passer rating. Jay Cutler's passer rating this past Sunday for example was 76.7, which is significantly below the league average. Now, let's consider whether the Dolphins' pass defense was responsible for Siemian's performance. Prior to the Denver game the Dolphins' pass defense surrendered an opponents' passer rating of 105.7, one of the worst figures of its kind in the league in 2017. In no single game in 2017 had it surrendered an opponent's passer rating below the mid-80s, roughly the league average. Siemian on the other hand had an overall 2017 passer rating in the mid-70s coming into the game, significantly below the league average, and had posted passer ratings in previous games of 43.5 and 58.2. The Dolphins beat the Broncos 35-9, largely because of Trevor Siemian's "gift" of an extremely poor game, in my opinion.