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Top free-agent linebackers
It's tough to put all the different types of linebackers under the same umbrella. Scheme dictates so much and there are no universal players who fit every scheme or position.
There are 3-4 outside 'backers hired to rush the passer, 3-4 inside 'backers big enough to take on a guard, 4-3 middle 'backers capable of dropping deep into Tampa-2 coverages, strongside 'backers able to cover tight ends and weakside 'backers who can be small as long as they can run and hit.
Here's my top-five list, which doesn't include any 3-4 outside linebackers.

The middle linebacker was in on 281 tackles over the past two seasons and is an ideal fit for any 4-3 team looking for a Mike linebacker. In 2010, Tulloch also had six passes defensed and an interception. He's 26 years old and should make the same kind of impact London Fletcher made when he went from the Rams to the Bills and eventually to the Redskins. Teams can figure on 100-plus tackles a season for the next few years.

A smart 4-3 middle linebacker who has also played in a 3-4 scheme. Posluszny can pick up a system quickly and should be ready to lead a defense in a short period of time. He has missed 19 games in his four-year career, but was in on 150 tackles and two sacks in 14 games this past season.

Burnett played inside in a 3-4 defense, but would easily fit in a 4-3 package. The 28-year-old Burnett completed his first 16-game season as a starter in 2010 after six years in the league. He picked a great time to be a free agent, after being in on 95 tackles, six sacks, two interceptions and two forced fumbles.

Ruud is purely a 4-3 middle linebacker who can make all the adjustments and quarterback a defense. He gets criticized by Buccaneers fans who perceive him as soft and making too many tackles downfield. If he leaves Tampa Bay, it might regret the loss. In his last four years, Ruud averaged over 100 tackles a season and has six interceptions, six forced fumbles and 20 passes defended during that span.

Black is a run-and-hit guy on the outside. If the Buccaneers lose both Barrett Ruud and Black, the defense will not be the same. Black is big enough to play over a tight end or stack behind a defensive tackle and run to the ball. He has only been a starter for the past two seasons, but is showing some blitz pass-rush skills to go along with his ability in coverage.

In Arizona, a guy like Joey Porter could end up on the market. It will be interesting to see what happens in Green Bay with Nick Barnett, and possibly another quality linebacker or two.