The key with defenses is finding defenses that will face a lot of passing plays. Fantasy point-scoring events like interceptions and sacks occur exclusively on passing plays, and fumbles actually occur more on passing plays than running plays. Defensive touchdowns are difficult to predict, but they're also more likely to occur on passing plays with 53 pick sixes last year compared to only 33 scoop 'n scores.

One of the best ways to identify defenses that will face a lot of passing plays is identifying Vegas favorites, preferably home favorites. And obviously the lower the opponent's implied point total, the better the matchup for the defense.

Premium Options

The chalk this week is Tennessee and Buffalo. Both teams are about touchdown favorites at home, and their opponents are tied for the lowest implied team total in Vegas at 18.25. Tennessee will host Cleveland who is tied for eighth in most fantasy points allowed to opposing defense per game. They're tied in that stat with San Francisco, which is who Buffalo will host. So as far as matchup goes, these teams are dead even.

But once you get past matchup, there are several reasons why Tennessee might be the better play. First, Tennessee has been the slightly better defense this season, though both have been good. Tennessee ranks seventh in Football Outsiders' defensive DVOA while Buffalo ranks 11th. Second, Tennessee is cheaper than Buffalo on both DK and FD and significantly so on DK. And finally, Buffalo seems as if they'll be the most heavily owned defense this week. So go with Tennessee and pay a bit less for the better, lesser owned defense.

Sneaky Options

This category is reserved for good defenses that may be overlooked in a given week for whatever reason, providing you with the opportunity to roster a really good unit with a lower ownership rate. 

Seattle certainly fits that bill this weekend. The Seahawks rank first in DVOA, but they don't figure to be too highly owned given that they're facing the team that ranks first in offensive DVOA, Atlanta. Vegas clearly thinks Seattle will win this battle of strengths with the Seahawks being a six-point favorite at home and with Atlanta having the fourth lowest implied total on Sunday. Seattle's price isn't overly appealing on DK, but they're priced well enough on FD and Aces.

Philadelphia trails only Seattle in defensive DVOA. The Vegas variable don't favor them nearly as much as Seattle as they're on the road and only a two-point favorite. Their opponent, Washington, has the eighth lowest implied total, which is good but not great. But if you're looking for a cheaper version of a good defense likely to be largely overlooked this weekend, Philly applies on DK and FD (not on Aces where they're the same price as Seattle).

Value Options

If you're looking to go as cheap as you can with your defense, Chicago may be your best bet. They're a 2.5-point favorite at home, and their opponent, Jacksonville, has a slightly below average implied total of 22.25. The Bears defense hasn't been good this year, but they rank a semi-respectable 18th in defensive DVOA to date. On DK, only two defenses are cheaper than Chicago on Sunday, and both of those teams rank bottom five in DVOA. On Aces the Bears are priced at the minimum.

The Bears are also a cheap option on FD, but New York is the same price and might be a preferable option there. The Giants have been a slightly better defense as they rank 16th in DVOA. They also have slightly more favorable Vegas variables as they're a three-point home favorite to Baltimore who has a lower implied total (20.5) than Jacksonville.