The Detroit Lions and Ndamukong Suh were one of the defensive squads that broke out in 2011.
They say defense wins championships.
Although that is not the case in fantasy football, a good defense can still score you 15 to 20 points a week. Sometimes the addition of just one or two skilled players can be the difference between a defense that is mediocre and a defense that gives quarterbacks nightmares.
Here are three teams that may have added the missing pieces to the puzzle and could be very effective in 2012.
The Philadelphia Eagles were among the NFL's most disappointing teams of 2011. After being dubbed the the "Dream Team," the Eagles were nothing more than mediocre, capping the year off with an 8-8 record.
The defense looked solid all around on paper but their Achilles heel was the linebacking corps. In the offseason, the Eagles were able to add DeMeco Ryans to help solve their problem at middle linebacker and improved the defensive line by drafting nose tackle Fletcher Cox.
Trent Cole, Jason Babin and Fletcher Cox should put plenty of pressure on opposing quarterbacks, which will lead to hurried throws and more interceptions for players like Nnamdi Asomugha and Dominique Rodgers-Cromartie.
The Buffalo Bills have been in the process of rebuilding their defense for the last two years and in this past offseason, they may have added the necessary players to make the Bills' defense one of the best in the league.
Elite pass-rusher Mario Williams left Houston to play in Buffalo and should wreak havoc alongside youngster Marcell Dareus.
The other key addition came via the 2012 NFL draft. The first-round draft pick, cornerback Stephon Gilmore, has Pro Bowl potential and should make an immediate impact.
Despite making an appearance in Super Bowl XLVI last season, the New England Patriots had the worst defense in all of football.
To no one's surprise, the Pats had a very impressive 2012 NFL draft and added premier talent when they drafted defensive end Chandler Jones out of Syracuse and linebacker Dont'a Hightower out of Alabama.