Choosing a defensive unit in your fantasy draft — and sticking with it for the entire season — is an outdated way to envision your roster. Instead, you should be looking for the best possible weekly matchup with whatever defenses are available on the waiver wire. That way, you should be able to get above-average performance at the position for the year without worrying if you made the right choice on draft day.

The key to this strategy is to roster defenses playing against teams that are either at a disadvantage in the trenches or aren’t expected to win many games. Such offenses should be playing from behind more often than not, making them more predictable and prone to mistakes. For example, over the past three seasons, NFL teams that were trailing by four to 10 points passed the ball 60 percent of the time, with higher interception, sack and fumble rates than teams leading by four to 10 points. Teams with offensive lines expected to struggle this season include the New York Giants, Carolina Panthers and Miami Dolphins.

In 12-team leagues, an average of 15 defenses are being drafted, according to data from Fantasy Football Calculator, leaving around 17 undrafted defenses to choose from during the early parts of the season. Not all of those units will be fantasy viable, but the chances of an undrafted team finishing a given week among the top five fantasy defense/special teams units is roughly as good as for those that are drafted.

Over the past three seasons, 43 out of 46 defensive units that were drafted in at least one Fantasy Football Calculator mock draft have finished in the top five of weekly defensive scoring at least once during the season, a nearly identical rate to that of the undrafted teams (46 out of 50). That trend also mostly held when looking at defensive units that appeared at least four times in the weekly top five in a given season: 16 of the 46 drafted defenses compared to 13 of the 50 non-drafted defenses.

Drafted defensive units have averaged 6.3 fantasy points per game in a typical fantasy scoring system, compared to 6.1 points per game from the undrafted teams. In other words, you are better off planning on playing the best matchup you can find rather than worrying in early September about which defenses will end the season as the best.

And there are plenty of opportunities to make the most of weekly mismatches, especially by paying attention to defensive lines, where the most dependable defensive fantasy points — from sacks — originate. More than two-thirds (39 percent) of the defensive fantasy points in standard scoring systems from 2018 to 2020 came from sacks. The next highest contributor was interceptions (26 percent), which can be fluky and tough to predict, followed by fumble recoveries (16 percent) and defensive touchdowns (15 percent). Good luck trying to predict those two with any certainty. Instead, just go with the advantage in the trenches.

One defense probably overlooked in this year’s drafts: the New York Jets. Pro Football Focus ranks New York’s defensive line as the seventh-best headed into 2021. Defensive tackles Quinnen Williams and Folorunso Fatukasi ranked 10th and 13th at the position (out of 50 qualified players) by Pro Football Focus last season. Defensive end John Franklin-Myers finished 2020 with three sacks, four hits and 23 hurries. Defensive tackle Sheldon Rankins and defensive ends Vinny Curry and Carl Lawson arrived in free agency, with Lawson producing 64 total quarterback pressures for the Cincinnati Bengals last season and earning the ninth-highest pass-rushing grade among edge rushers from Pro Football Focus. The Jets also added pass rusher Shaq Lawson in a preseason trade with the Texans.

In Week 1, the Jets will face the Carolina Panthers, who employ what PFF projects as one of the worst offensive lines of 2021. In Week 3, it’s the Denver Broncos, whose offensive line projects near the bottom third of the NFL. In Week 8, the Jets will face the Bengals (25th). And in Weeks 11 and 15, the latter a typical fantasy football playoff game, New York will try to dominate the Dolphins and the projected fourth-worst offensive line in football.

Here’s how you can plan to stream defenses for those weeks and the rest of the season with defenses that are unlikely to be drafted.

Week 1: New York Jets vs. Carolina Panthers

Week 2: New Orleans Saints vs. Carolina Panthers

Week 3: New York Jets vs. Denver Broncos

Week 4: New Orleans Saints vs. New York Giants

Week 5: Philadelphia Eagles vs. Carolina Panthers

Week 6: Green Bay Packers vs. Chicago Bears

Week 7: Philadelphia Eagles vs. Las Vegas Raiders

Week 8: New York Jets vs. Cincinnati Bengals

Week 9: New Orleans Saints vs. Atlanta Falcons

Week 10: Arizona Cardinals vs. Carolina Panthers

Week 11: New York Jets vs. Miami Dolphins

Week 12: Philadelphia Eagles vs. New York Giants

Week 13: Philadelphia Eagles vs. New York Jets

Week 14: Green Bay Packers vs. Chicago Bears

Week 15: New York Jets vs. Miami Dolphins

Week 16: Philadelphia Eagles vs. New York Giants

Week 17: New Orleans Saints vs. Carolina Panthers