San Francisco 49ers (Photo Credit: Ezra Shaw/Getty Images)

The adage “defense wins championships” matters much more in the National Football League than in fantasy football. But a strong defense/special teams unit could be the difference between bragging rights and second place. So with less than a month until the NFL kicks off the 2012 season, let’s huddle up and break down the top Ds/STs to target on draft day.

1. San Francisco 49ers

Led by the Smiths (Justin and Aldon) and Patrick Willis, the Niners defense enters the approaching season as the league’s premier point-stopping unit. Consider this: San Francisco forced multiple turnovers in 13 regular-season games last season and didn’t allow a rushing touchdown until Week 16. The 49ers’ defense scored only one touchdown in 2011, but defensive points — often the result of luck — can drastically fluctuate from year to year.

Chicago Bears (Photo Credit: Jonathan Daniel/Getty Images)

2. Chicago Bears

Football’s Windy City club scored six defensive touchdowns during the 2011 season, which greatly enhanced its fantasy value. Led by a future Hall of Famer in Brian Urlacher, Chicago’s defense has been one of the league’s top units year in and year out. Add in return man Devin Hester — one of the best the sport has ever seen — and you have yourself a top-3 D/ST selection for 2012.

3. Philadelphia Eagles

Philadelphia Eagles (Photo Credit: Chris Trotman/Getty Images)

The Eagles defense, which employs arguably the best cornerback tandem in the NFL in Nnamdi Asomugha and Dominique Rodgers-Cromartie, racked up a solid fantasy effort in 2011. The unit recorded four defensive touchdowns — including three after Week 8 — and tied the Vikings for the most sacks (50). The off-season acquisition of linebacker DeMeco Ryans should only help. Rookie Brandon Boykin, the team’s projected primary return man, is looking to replace DeSean Jackson, a talented wide receiver whom the Eagles need to protect from injury.

4. Houston Texans

If the NFL awarded a “most improved defense award,” it would’ve gone to the Texans in 2011. The unit made major strides under defensive coordinator Wade Phillips — going from near the bottom to near the top in many categories — and enters this season as a relevant fantasy option. And that’s with the loss of Mario Williams, who bolted for the Buffalo Bills (and spent much of last season on injured reserve anyway). Look for this young group to continue their growth.

5. New York Jets

Gang Green’s 2011 defense was middle of the road in terms of points allowed, but has the potential to turn it around. Led by cornerback Darrelle Revis, the Jets surrendered the fifth-fewest passing yards per game (201) and tied for tenth with 19 picks (including two returned for scores). The Jets also forced an NFL-best 23 fumbles last year, recovering 12 and scoring on one. Return man Joe McKnight has the potential to be one of the sport’s best specialists.

Baltimore Ravens (Photo Credit: Jeff Curry/Getty Images)

6. Baltimore Ravens

Baltimore’s defense would be ranked much higher had Terrell Suggs not torn his Achilles during the off-season. The unit, led by legendary linebacker Ray Lewis and defensive tackle Haloti Ngata, still projects to be pretty formidable. Safety Ed Reed, a former defensive player of the year who’s looking for a new contract, may just have something more to prove. And Suggs could return at some point. Return man David Reed gets the job done, when he’s healthy.

7. Green Bay Packers

This wouldn’t be the unit to necessarily own in real life; they finished 32nd in defense in 2011. But Green Bay’s porous defense dominated the turnover game last season. With seven fumble recoveries and a whopping 31 interceptions, they finished atop football’s takeaways leader board last year. (The Niners also collected 38.) The team focused on defense in the draft, using their first six picks on defenders. And don’t forget return man Randall Cobb, who tied the record for longest kickoff return (108 yards) last year.

Seattle Seahawks (Photo Credit: Jay Drowns/Getty Images)

8. Seattle Seahawks

Seattle’s defense fared well last fall and should again impress, especially if first-round pick Bruce Irvin pans out at defensive end and helps what was, at times, a very weak pass rush. Leon Washington is a very talented return man despite failing to take any to the house in 2011 (he got there three times the year before). Washington had an impressive return average last season, and should find the end zone again during the upcoming campaign.

9. Pittsburgh Steelers

The Steelers’ D and special teams each scored just one touchdown in 2011; the defense only accounted for 15 turnovers. But a team that allowed the fewest yards in the NFL needs to be on this list. The defense will be led by Troy Polamalu, LaMarr Woodley and James Harrison, despite his ongoing knee problems. And that turnover number should bounce back if they remain reasonably healthy. Wideout Antonio Brown, who made the Pro Bowl last year after recording more than 1,000 receiving yards and 1,000 return yards, is a threat in the return game.

10. Buffalo Bills

The Bills have greatly improved their defense over last season’s squad. They brought in premier pass rusher in Mario Williams (the man drafted before Reggie Bush) and then splurged on end Mark Anderson, who tallied 10 sacks for the Patriots in 2011. Factor in the continued development of d-lineman Marcell Dareus, the third overall selection in last season’s draft, and the Bills begin to look pretty fierce on the defensive side of the football. The already formidable secondary, which added cornerback Stephon Gilmore in the first round, should benefit from the pass-rushing help. Owners looking for a defensive steal should keep an eye on the Bills’ D.

Waiver Wires

Some fantasy managers may opt to play the match-ups and pick up defenses off the waiver wire. Those who go this route should target the Minnesota Vikings, who open the season against the offensively challenged Jacksonville Jaguars and then the Indianapolis Colts (2-14 last year) and rookie quarterback Andrew Luck.

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Zachary Finkelstein is a contributing writer to CBS Local Digital Media and a graduate of Northeastern University.