Now it's time to flip the script.
Here's a look at five clubs around the league that are promising to do things differently on defense in 2013:
New Orleans Saints
The Wide-9 has gone the way of the carrier pigeon in Philadelphia, where all signs point to a three-man front for the Eagles. New defensive coordinator Bill Davis has been given freedom to mold this unit to his liking, but he's preaching patience.
"This year is absolutely the hardest transition year we're going to have," Davis told the Philadelphia Inquirer.
Kelly -- surprise, surprise -- wants "versatility," and Davis emphasized he'll build a "multiple" unit. Expect to see more blitzes than under Juan Castillo.
Top 100 Players of 2013
Bradley is fashioning a 4-3/3-4 hybrid attack and hinted this week that end Jason Babin fits in well as a right-side-rushing Leo chess piece. "He has a lot of the traits that we're looking for," Bradley said.
The Browns have promised to attack on offense, and Ray Horton's defense boasts a similar philosophy.
After two years in the 4-3, Cleveland is shifting back to the 3-4. Success boils down to the play of pass rusher Paul Kruger and defensive end Desmond Bryant, both of whom were handed a mountain of money in free agency to make Horton's scheme click. First-round pick Barkevious Mingo will play outside 'backer opposite Kruger and gives the Browns a potential X factor up front.
Monte Kiffin's 4-3 is coming to town, meaning DeMarcus Ware and Anthony Spencer will move from outside linebacker to end. Cowboys fans shouldn't lose any sleep over Ware. He's a dominating seeker of quarterbacks, and he will continue to generate chaos with his hand in the dirt. Spencer is less of a lock to see equal production.
That's far from surprising. All these defenses have a preferred core alignment, but the trend in today's NFL is scheme flexibility. Adapt or vanish.