These rankings are for the purpose of predicting how many fantasy points defenses will allow to offensive players this week.
We are now using only 2012 data. But there are some big changes relative to last year. The most improved defenses by these rankings from 2011 to 2012 when it comes to allowing fantasy points by the opposition are the Lions (up 74 ranking points), Buccaneers (plus-61), Packers (plus-53), Vikings (plus-52) and Patriots (plus-41). The defenses that have fallen the furthest measured the same way: Titans (minus-74), Ravens (minus-65), Steelers (minus-64), Jaguars (minus-62), Saints (minus-53). The key takeaway here is that you do not want to go out of your way to matchup marginal guys against 2011 easy marks Detroit and Tampa Bay. Similarly, there's no longer any need to sit your regular starters against the Ravens and Steelers.
If you have other questions relating to matchups, feel free to ask them via Twitter @MichaelSalfino. I cannot emphasize enough that these defensive rankings have nothing to do with which defense to play in fantasy.
This week's highlighted matchups follow after the chart. But first a word about the categories. Only "Red Zone" is a little tricky. We're not talking efficiency there, but rather red zone possessions allowed. Red zone possessions have proven over many years to be more useful in predicting future defensive performances. RYPG is rushing yards per game. RTD/G is rushing TDs per game. PYPG is passing yards per game. PTD/G is passing TDs/per game. Yardage allowed is more reliable than touchdowns allowed for predictive purposes. Ideally, the two correlate. But some teams really can be break but don't bend, e.g., teams that blitz a lot.
Defensive Power Rankings
Teams are sorted by cumulative rankings in all categories. Lowest total number is best; highest is worst.
Matchups to exploit
Vikings vs. Titans (32): Tennessee's defense is terrible in every way. So you not only are likely to get big days from Percy Harvin and Adrian Peterson, but Kyle Rudolph is a good bet to have the type of game his owners expected when drafting him. And if Jerome Simpson is available in your league, pick him up and start him at your flex. Also, Christian Ponder is a great sneaky play, too. Remember, last week, those who thought Ponder would put up huge numbers against Detroit were still in 2011 mode. That kind of game is coming in Week 5.
Chargers at Saints (31): If Ryan Mathews doesn't explode here, he can officially be called a bust irrespective of the injury woes most were aware of when they drafted him. There should be at least one goal-line plunge for Jackie Battle to steal, too. Malcom Floyd has also been a big disappointment and it's a put up or get cut day for him, too, in the eyes of his owners. Philip Rivers should bust out for 20-plus fantasy points, too.
Matchups to avoid
Bills at Niners (1): San Francisco is nasty. If you have Ryan Fitzpatrick as a backup, you should trade him now because his value will plummet after this week. Stevie Johnson has scored in all but one game and had an easy touchdown last week that Fitzpatrick blew with a poor throw, but his yards and catches have been low. That is not likely to change this week. If you own C.J. Spiller or Fred Jackson, you want the other guy to get the carries on Sunday because that guy will get chewed up and spit out (and maybe get banged up, too).
Panthers vs. Seahawks (3): You're not going to play any Jets against No. 2 Houston. So we move on to this game. Don't expect that long-awaited Steve Smith breakout this week. The Panthers may run, though, because of how teams do defending the run against everyone else doesn't really matter versus Carolina and especially Washington, because Cam Newton and Robert Griffin III alter defensive principles. But Newton owners are going to need a big day on the ground because it's very hard to see many yards coming via the air. Forget about Greg Olsen this week, too.
Steelers vs. Eagles (6): Philly is especially tough against the pass. So you want to avoid Ben Roethlisberger if you are pairing him with a comparable quarterback or even if you are not. For example, Ponder over Roethlisberger this week. The Eagles are more susceptible on the ground so maybe Rashard Mendenhall is a flex play in his first game back from this 2011 Week 17 ACL injury. Forget about Heath Miller but still play Antonio Brown or Mike Wallace, though there is virtually no chance that both guys have big days. Yes, I know that Victor Cruz and Domenik Hixon were big last week, but the Giants have more experience in how to attack the Eagles defense.