Best, worst Week 5 matchups

By the numbers, Philip Rivers and Antonio Gates are strong plays in fantasy this week. USA TODAY Sports

Now that the season is about a quarter of the way over, we start to understand which teams are good and which are bad. Furthermore, we have a better understanding of why some teams are good and some, such as the one in Jacksonville, are so bad.

At Football Outsiders, the key efficiency metric DVOA (explained here) stands for defense-adjusted value over average. However, for the first four weeks we were basing matchups just on VOA, as it was too early to apply opponent adjustments at any strength. Now we can do that, making the "D" a factor that is essential to studying this game.

After all, the NFL is a matchup league. What works against one opponent may not against another.

When Peyton Manning threw seven touchdowns against Baltimore in Week 1, we could only naively assume the Ravens were one of the worst pass defenses in football. But with more data the past three weeks -- Baltimore has allowed two total touchdowns (one passing) since -- we can see that the Ravens (No. 12 in defensive DVOA and No. 16 against the pass) are not that bad.

We also are quickly learning that Denver is just that good. Manning has 16 touchdown passes in four games, which is already more than 155 teams have had in a full 16-game season since 1988. As I mentioned last week, if you have Denver receivers on your fantasy team, start them every week. If you don't have them, maybe trade for one if you are in need.

Denver's big four pass-catchers are all nearly on pace for 1,000 yards: Demaryius Thomas (1,592), Eric Decker (1,360), Wes Welker (1,064) and Julius Thomas (948). When you look at the remaining schedule, it's not out of question this could be the first offense in NFL history with four 1,000-yard receivers.

Here are the best and worst fantasy matchups for Week 5: