The 2010 season was all about installing a new defense. The 2011 campaign: adding better tools, and sharpening those already in use. Now, Washington Redskins defensive coordinator Jim Haslett and his players hope that 2012 marks their rise to dominance.

There were plenty of growing pains in 2010. As they learned new positions and philosophies on the fly, the Redskins took their lumps, finishing the year ranked 31st out of 32 defenses.

But last season, with a year in the 3-4 scheme under the belts of linebackers Brian Orakpo, London Fletcher and Perry Riley and defensive end Adam Carriker; after drafting outside linebacker Ryan Kerrigan and the free agent signings of nose tackle Barry Cofield and end Stephen Bowen, Washington featured a much more formidable defensive front.

With improved ability to get to the quarterback, the upgraded front seven powered the defense’s rise to 13th in the league. The Redskins, who mustered only 29 sacks in 2010, racked up 41 in 2011.

Over the past offseason, the Redskins accomplished two key goals, re-signing both Fletcher and Carriker, whose contracts had expired. The signings ensured that the front seven will remain intact. The hope is that continuity breeds further success.

“When the Pittsburgh Steelers went to the 3-4 back when Bill Cowher took over their first year, they were 25th,” Haslett said. “Their second year, they were 13th and their third year they were third . . . I do think that there is so much volume to it that it is a learning process. I am not saying that we are going to make those jumps. I’m just saying it takes a while to get players and, obviously, to understand. I think if you talk to the players, to a man, they feel good about it.”

Familiarity has lent itself to more flexibility and creativity. Haslett plans to use Cofield on more stunts, making him more of a factor in the pass rush. And the coach will have Orakpo and Kerrigan switch sides to take advantage of mismatches rather than just restricting them to right and left, respectively.

“We’re just being creative out there as a defensive front,” Orakpo said. “Whether it’s lining up on either side, moving around, if it’s a three-down look and me being the spinner. It’s just us, trying to create more mismatches and take advantage of it. We’re doing all that.”

Another factor in the anticipated progress is the return of defensive end Jarvis Jenkins, the 2011 second-round pick who, after making an impact during his rookie preseason, was lost for the year with a torn anterior cruciate ligament.

Jenkins will come off the bench, rotating primarily with Carriker and Bowen, but Haslett views the Clemson product as a key cog in his defense. With his ability to play all three defensive line positions, Jenkins will help ensure that Washington’s linemen remain fresh and effective as they wear down offensive linemen.

“[Jenkins] will end up playing nickel, he’ll play base, so I love the depth we have up front right now. He is a key,” Haslett said. “We thought Barry had way too many snaps last year. We would like to reduce that a little bit. Obviously, having Jarvis back will give us that flexibility.”

The biggest questions on defense concern the secondary, where Washington ranked among the worst in the league statistically last season and has retooled during the offseason.

DeAngelo Hall and Josh Wilson return at the cornerback positions, but last season’s oft-injured safety tandem of LaRon Landry and Oshiomogho Atogwe has been replaced, and last year’s nickel back, Kevin Barnes, was traded to Detroit in the final week of the preseason.

The Redskins signed former two-time Pro Bowl strong safety Brandon Meriweather, who fell out of favor in New England and wasn’t a good fit in Chicago last season, to replace Landry. Former Maryland star and Minnesota VikingMadieu Williams will start at free safety. Tanard Jackson was in line to see time at both positions before he was suspended indefinitely last week for a third violation of the NFL’s substance abuse policy. Cedric Griffin will be the third cornerback.

Hall calls the defensive backfield a “secondary of misfits.” He, Meriweather, Williams and Griffin all have been rejected by other teams — in some cases multiple teams. But he and his teammates use the past as motivation.

“We all laugh at some of that stuff because we all know that at the end of the day you have to go out on the field and prove it,” Hall said.

Haslett and new secondary coach Raheem Morris like the tools they have to work with. They view this group of players as a more versatile bunch who will make it hard for offenses to game plan for them.

Hall will, at times, start games at his usual outside corner position, then move to the inside to cover slot receivers as Griffin joins the starters on the field. At other times, Hall or Wilson may slide back to safety while Meriweather or Williams move up to cover a wide receiver.

“You have a lot of different things [that we can do],” Haslett said of his defensive backs’ versatility.

He added: “We’re going to try and win games. We’re going to do whatever we can to do to get turnovers. We’re going to do whatever we can to keep the points down. And we’re going to do whatever we can do to help the offense get the ball back. I think that is the most important thing.”