ESPNChicago is examining potential unrestricted free agents at various positions of need for the Chicago Bears.

It's hard to remember the last time linebacker wasn't considered a strength of the Bears' defense. With all the player movement in the NFL, the Bears have experienced little turnover at linebacker, essentially relying on five players over the last eight seasons: Brian Urlacher, Lance Briggs, Nick Roach, Hunter Hillenmeyer and Pisa Tinoisamoa -- Jamar Williams, Geno Hayes and Blake Costanzo also made occasional contributions but nothing sustained over a long period of time.

That is an impressive core, to say the least, led by Urlacher and Briggs, who together have a combined 15 Pro-Bowl appearances. But let's not overlook the above average play provided by Roach, Hillenmeyer and Tinoisamoa primarily on the strong side, although both Roach and Hillenmeyer did commendable jobs filling in at middle linebacker whenever Urlacher was unable to dress due to injuries.

All that consistency from the five veterans covered up the fact the Bears had a difficult time drafting linebackers in the last six years, starting with a wasted third-round pick on Michael Okwo in 2007, followed by a miss on Marcus Freeman in the fifth round of the 2009 draft. Neither Okwo or Freeman ever played a down for the Bears in the regular season. J.T. Thomas, a sixth-round choice in 2011, began to emerge last year on special teams, but it's unknown if he's ready to challenge for playing time on defense. Hayes had the best resume of all the non-starters on the roster last year, but he is scheduled to be an unrestricted free agent. The rest of the linebackers under contract look better suited for special teams, at least at this juncture of the offseason.

Urlacher remains one of the biggest question marks of the offseason. Even if the Bears do bring back the future Hall of Famer, there is still a need for this team to get better at linebacker.

There is no doubt the Bears will be looking at linebacker in the upcoming draft, but in the event general manager Phil Emery believes the club needs to add an experienced linebacker to replace Urlacher or Roach, who is also a UFA, here is a quick look at some of the 4-3 linebackers who might be available when free agency begins on March 12., in no particular order.

Also, it's entirely possible the Bears could eventually transition to a 3-4, but with so many key veterans still under contract, new defensive coordinator Mel Tucker might be inclined to keep the 4-3 look and try in his own set of wrinkles.

Philip Wheeler, Oakland Raiders: Wheeler had his finest NFL season last year for the Raiders when he started all 16 games at outside linebacker and recorded 109 tackles, 3.0 sacks and forced a pair of fumbles. Wheeler spent his first four seasons in the league in Indianapolis before signing a one-year deal with Oakland last offseason. It turned out to be an excellent move for the Raiders, who will certainly try and lock up Wheeler to a long-term contract. But if he's available, Wheeler seems to fit the mold of the type of player the Bears are looking for.

Justin Durant, Detroit Lions: The Bears made a run at Durant two years ago in free agency before he signed a two-year, $5.5 million deal with Detroit following the NFL lockout. Durant has played well in a Lions' uniform, registering 103 total tackles, while missing limited time due to injuries.

Rey Maualuga, Cincinnati Bengals: It's fair to say Maualuga's career has been up and down. On one hand, he's a 26-year-old middle linebacker with loads of experience coming of a 122-tackle season. On the other hand, Maualuga's struggles, especially in coverage, have been obvious to even the most casual fan. It sounds as if he could use a change of scenery, but what kind of player are you getting? And for what price? This has high risk/high reward written all over it.

Rocky McIntosh, St. Louis Rams: The Bears had McIntosh in for a visit last offseason but took a pass. McIntosh eventually landed in St. Louis where he started nine games for the Rams. The 30-year-old veteran had a good run in Washington where he lasted six seasons.

Erin Henderson, Minnesota Vikings: Henderson has emerged the last two seasons, making 21 starts at weakside linebacker for the Vikings. While the Bears appear set on the weak side with Briggs, the team has always maintained the linebacker spots are interchangeable. Making a run at Henderson might not only potentially strengthen the Bears, it would also possibly weaken a divisional foe.

Jasper Brinkley, Minnesota Vikings: Brinkley started 15 games at MLB for Minnesota last year where he had 99 tackles and three forced fumbles. He's viewed as a good two-down linebacker who normally came off the field in the nickel package.

Kaluka Maiava, Cleveland Browns: Maiava is a bit on the shorter side at 5-foot-11, but he showed in Cleveland that he can play both weakside and strongside linebacker where he put up decent numbers despite sharing playing time. Maiava is considered a solid coverage linebacker with a strong background on special teams.

Chase Blackburn, New York Giants: Blackburn has played eight seasons in New York and made 98 stops at MLB in 2012. He had been a reserve most of his career but has two Super Bowl rings to show for it.

DeAndre Levy, Detroit Lions: The outside linebacker has started at least ten games in each of his four NFL seasons in Detroit. His best year came in 2011 when he tallied 109 tackles.

Thomas Howard, Cincinnati Bengals: Howard had several productive years in Oakland before jumping to Cincinnati in 2011 where he had 99 tackles in 15 starts. But he tore his ACL in Week 1 last season, which is sure to impact his stock in free agency.