Run and hit, seek and destroy, defend the run, play the pass. Linebackers, they do it all and they are the life force of a team’s defense.

All unique in their responsibilities, each position plays off one another in synergy, flowing to the football, shooting gaps, or dropping back into coverage.

The MIKE ‘backer is normally the captain of a team’s defense, tasked with calling plays, and making sure defenders are aligned and focused on their keys. A good MIKE is normally a tackling machine, rarely out of position and in the middle of the action. Having a good to great middle linebacker is imperative for a team to be good on defense.

SAM ‘backers are normally enforcers, responsible for setting the edge against the run, making sure the defense’s strong-side holds strong. Usually a liability in coverage, SAMs are often subbed for nickel backs, especially on defenses with four man fronts.

The WILL ‘backer can sometimes be so good, they’re the best player on an entire defense. Think HOF’er Derrick Brooks in his heyday for an example of a 4-3 WILL. In a 3-4, teams are looking for an elite pass rusher in the mold of a Clay Matthews before the position switch inside this year. With offensive schemes becoming so intricate in today’s game, the linebacker position is as integral a part as it’s ever been to a defense’s success.

This offseason there will definitely be teams looking for an upgrade in the second level of their defense which will create heated bidding wars in free agency for teams looking to retain their players and avoid having to fill a glaring hole themselves or jockeying for the services of their target acquisitions.

Here’s a ranking of the top impending free agents at the linebacker position.

1. Justin Houston

A premiere pass rusher in this league, Justin Houston is a stud. The best player on the Kansas City Chiefs with 39.5 sacks in 48 games, Houston is a nightmare for opposing quarterbacks rushing off the edge. With 13 sacks in 11 games during a contract year, a strong assumption can be made that Houston will earn a new contract before the end of the year or earn himself the franchise tag designation. One main reason he should earn a mega contract would be his exemplary leadership skills. It’s obvious he is mature beyond his years and head coach Andy Reid has noticed.

“I’ve seen it at practice every day,” Reid said of Houston’s leadership. “He puts a lot of pressure on himself. He also puts it on the players around him, but he has a personality where he’s funny. He can kind of keep it loose. He knows when to crank it and when to loosen it up.

“He’s developed a good feel for that.”

The best option free agency has to offer at the second level of defense, Houston is going to bank major dividends during free agency because he’s truly that good. Houston has the make up of a perennial All Pro, what team wouldn’t want a player of that caliber on their squad?

2. Jason Worlids

Not the biggest name available this off-season, nor the most productive, but the Pittsburgh Steelers pass rusher is in a prime position to capitalize on hitting the open market at the right time at a position of demand. As a hybrid pass rusher who can play linebacker in the 3-4 and defensive end in the 4-3, Worlids will be a player in demand this off-season.

With 21.5 career sacks and just recently becoming a full-time player last year; Worlids will cash in at the ripe age of 26 years old based on potential. Getting compensated well after receiving the transition tag last year, his play has been inconsistent and that hasn’t been lost on the Steelers head coach.

“He’s had some good games and performances in pockets of games, and he’s had some games where he’s been less impactful,” Steelers’ head coach Mike Tomlin said when asked about Worlids. “We’re compensating him to be consistently impactful, and that’s what we’re searching for.”

This perception of Worlids among the coaching staff most likely means the front office will re-evaluate his price tag again come free agency time. This will more than likely leave Worlids free to test the waters where he’s likely to find a team hungry for a young experienced pass rusher such as himself.

3. David Harris

The need for a tough, dependable, intelligent middle linebacker is always a necessity in football and Harris embodies all of those qualities. A tackling machine who has been the leader of Rex Ryan’s defenses over the years, the eight year veteran is in his prime, having not missed a game since 2008. Coming off of back-to-back 120-plus tackle seasons, Harris is on pace to register another 100-plus tackle campaign.

An every down ‘backer who is pretty good in all aspects of the position, Harris is equally effective at rushing the passer as he is stuffing the run, his below average coverage ability is starting to show his gradual decline after being pretty good in this regard to start his career.

Recognized in his locker room as a play maker and leader, New York Jets head coach Rex Ryan appreciates his defensive captain’s ability.

“David Harris is the most underrated player in the league,” Ryan said during the past off-season when Harris was left off of the NFL Network’s Top 100 list.

At 30 years old with a proven track record of durability, there’s no reason to doubt Harris will remain an effective player for another three to four years. Despite his decline in pass coverage, Harris will always be valuable as a two-down player. Best suited on a team with a rising star on the inside of a 3-4 alignment, a team looking at Harris for a scheme change to anchor a 4-3 defense may be disappointed with their investment.

Reliable and durable players are always revered and held at a premium in this league. The best ability is availability and when it comes to that, Harris is special. Look for Harris to draw interest from a couple of 3-4 defensive teams looking for a heady veteran to solidify their front seven, but expect the veteran to take a home town discount to end his career with the only team he’s ever played for.

4. Brain Orakpo

Probably the biggest name in free agency at the linebacker position, Orakpo was enduring his worst statistical season as a pro before tearing his pectoral muscle against Tennessee this season. For his career, Orakpo has always been a dependable pass rusher with the versatility to be both stout versus the run and a headache for tackles when chasing the quarterback. Even with the lack of sack production, Orakpo’s injury was still a tough blow for the Redskins defense.

“The production may not be where people think it should be, but he’s still been playing very good against the run and been disruptive in the passing game,” Redskins head coach Jay Gruden said . “That’ll be a big loss.”

Regardless of Orakpo’s injury, it wasn’t an injury to a lower extremity and he is still 28 years old. The three-time Pro Bowler will have suitors on the open market who need a player of his ilk. While not an elite pass rusher, Orakpo is just a notch below that when healthy, offering a consistent pressure presence that any defense could benefit from.

5. Jabaal Sheard

The Cleveland Browns rotation pass rusher that converted from a 4-3 defensive end into a hybrid outside linebacker has played well, despite, maybe being out of position and in a scheme that doesn’t best suit his skills.

The issue is that Sheard hasn’t developed into the pass rusher, playing in space that he was would become. Sheard was actually a better pass rusher as a down linemen, but either way Sheard is a talent and is stout versus the run.

“Jabaal Sheard is a guy that’s kind of under the NFL radar,” said Browns’ head coach Mike Pettine about the pass rusher. “He’s a guy that plays that position violently.”

At only 25 years for age and in his fourth season as a pro, Sheard has an abundance of talent for any coach to work with and the versatility to fit into any system in the league. With the Browns invested in Paul Kruger and former first-round pick Barkevious Mingo, the Browns may be letting Sheard hit the open market and test the waters where he is sure to have plenty of suitors.

On Deck

1. Mason Foster

The Tampa Bay Buccaneers middle linebacker has all the tools you look for at the position. Able to run and diagnose running plays, Foster is a fine young player. Consistently around the football and adept to making plays in all phases of the game, Foster has plenty of room for growth. A starter since day one, the amount of experience Foster has been able to accumulate in the first four years of his career is invaluable. One of the leaders of the Buccaneers defense, it’s hard to think the Bucs would let any of the few good players they have hit the market.

Although, with Foster’s struggles this year in Lovie Smith’s system, it’s possible Smith and the rest of the front office may look for Foster’s replacement in the off-season. Provided that’s if said coaching staff makes it through the off-season.

2. K.J. Wright

The Seattle Seahawks linebacker has started over 51 games in his first four years in the league. He is unique in the sense that there are very few players on the open market who will have had his kind of productivity. Able to keep last year’s Super Bowl MVP on the bench for most of his career, that alone speaks to the ability in which Wright possesses.

At 6-foot-4, 240 pounds, Wright offers the Seahawks an imposing figure in their linebacking core. The Seattle front office will have their work cut out for them this off-season trying to figure out how to keep their two free agent linebackers. Wright will be a player, that if he finds his way onto the open market, teams will be heavily calling for his services. Wright’s versatility and size allow him to play on both the strong and weak sides, making him a player that is more valuable due to his versatility.

3. Malcolm Smith

The Super Bowl XLVIII MVP is a prototypical 4-3 weakside linebacker. Fleet of foot, built for chase and pursuit, the Seattle Seahawks four-year veteran was a part time role player until stepping up during last year’s Super Bowl run. Smith still remains a part time player, serving as a coverage specialist, utilizing his foot speed as an asset to handle weapons all over the the formation.

“He has tremendous skills and he’s really fast, fast like a defensive back or running back,” the Seattle Seahawks head coach Pete Carroll said last week. “He’s a natural athlete as well, so it comes really easy to him. He’s really grown in his toughness and his tackling and his aggressiveness, playing block protection and all of that stuff. He’s always been a great athlete, speed athlete, quickness and all of that.”

Young and talented, Smith has the skill to generate quite a bit of interest of teams that think he can blossom with more opportunity. Battling injuries most of this year, he’s going to have to prove he can be durable with an increased role as an every down ‘backer.

Best of the Rest

This off-season will feature quite a few quality role players and individuals looking to regain form after recovering from season ending injuries. That list of players includes restricted free agent Brandon Marshall and unrestricted free agents Rey Maualuga, Sean Weatherspoon, Brandon Spikes, Brooks Reed, Bruce Carter, Colin McCarthy, Casey Matthews, and Rolando McClain.