You've been prepping for this week for a while now. Prices came out for Week 1 of the daily fantasy football season over a month ago, meaning you've been staring at these salaries for weeks on end, hoping to find the right combination to spring you to the top of the leaderboards.

Then one injury rolls in.

And another.

And, yeah, another.

Crap.

Sure, it's great to get the value that comes with these new opportunities, but it also means you're forced to deviate from the matchups that got you so excited when you first glanced at the schedule. It's hard to pass up a shot at great value when it's sitting right in front of you.

This is what makes NFL DFS fun, though. You don't have to use all of those value options in your lineups. You don't have to use any of them if you don't want. What they give you is the flexibility to be creative in the way you structure your lineups, and that's why we should still be jazzed about those matchups that got our juices flowing before.

As we'll do every week here on numberFire, let's sort through five matchups we can exploit this week for daily fantasy football. We can spot these matchups using numberFire's Net Expected Points (NEP), the metric we use to track the efficiency of players and teams with the team totals being schedule-adjusted.

Here's how NEP works. Prior to each play, there's an expected number of points the offense will score on its current drive. A three-yard completion on third-and-two picks up a first down, thus increasing the expected points and giving the offense positive NEP. That same three-yard completion on third-and-four, though, will likely lead to a punt, resulting in a drop in NEP. Tracking these fluctuations over the course of a season can give us a solid idea of which units operate in the most -- or least -- efficient manner.

If you're a premium subscriber, you can also check these out using our matchup heat map. This lays out the same metrics right in front of you so you can see when an efficient passing offense is facing one that struggles to stop opposing quarterbacks. You can use this as the jumping off point for spotting matchups each week that you find juicy.

With all of that said, let's get it cranking. Here are five matchups you should exploit in Week 1 of NFL DFS.