Nate Silver’s FiveThirtyEight used an “Elo-based model” to predict the outcome of each game of the season, and the probabilities are based on 20,000 simulations. Elo, in short, is a “system that estimates each team’s skill level using only the final scores and locations of each game.” Slightly expanded:

Originally, our Elo formula started each franchise (at its founding) with a rating of 1500, which also represented the rating of an average team. This worked in general, especially since it had been a long time since the league had expanded. But it’s not such a good assumption for handling expansion teams and analogous situations, such as mergers between different leagues. Eventually, we determined that new franchises should be given a rating of 1300, and in conjunction with this change, we also regress teams toward a mean of 1505 (instead of 1500) after every season. This helps balance against the low ratings assigned to expansion teams, though it does mean the average team no longer carries a 1500 Elo rating …

Teams gain and lose ground based on the final score of each game and how unexpected the result was in the eyes of the pregame ratings.

As you can see above, the Eagles end up with a measly 3% chance to win the Super Bowl, but those are the fourth-best odds (though seven teams have a better chance). They also have an unlikely 49% chance to even make the playoffs, even though they’re projected to start 6-0.

Also, the Redskins are the only team with a sub 5% chance at winning their division.