The 2013 NFL free-agent pool is loaded with talent, and several marquee names are bound to end up elsewhere by the time this offseason comes to a close.
But there are several underrated defensive players who may not immediately come to mind as premier acquisitions, yet are nevertheless wise investments.
The impending draft class includes many playmakers on the defensive side. That said, there are plenty of relatively young pros who have proven to be assets at this level, which should trigger action from multiple teams struggling to stop opponents.
Here is one free agent from each layer of the defense who can cash in big once the free-agent market opens for business on March 9.
Henry Melton, DT
The Chicago Bears defensive tackle is only 26 years old and is extremely agile and disruptive on the inside at 6'3" and just under 300 pounds. He garnered a Pro Bowl selection in 2012, thanks to posting 32 tackles and six sacks, tied for third among players at his position.
Having a force from the inside that can collapse the pocket is an outstanding asset to have. Given Melton's youth, production and lack of injury history, he should be highly coveted.
Melton also had seven sacks in 2011 and continues to be one of the most under-the-radar players in all of football. But some may argue that his success was a byproduct of a successful Bears defense led by Julius Peppers, Brian Urlacher, Lance Briggs and a strong secondary.
Ultimately, though, that shouldn't be enough to scare buyers away, as Melton still put up stellar numbers despite having so many studs around him getting their share of big plays. He is clearly a great pass-rusher, but also holds his own against the run.
The market should reward Melton with a huge contract, which the Bears may not be able to afford, especially if they want to bring Urlacher back.
Dannell Ellerbe, ILB
The controversial, possible defensive holding call overshadowed the San Francisco 49ers' final offensive drive in Super Bowl XLVII.
It was Ellerbe who ran from the complete opposite side of the field to stop Niners RB Frank Gore from scoring. That play set up the Baltimore Ravens' goal-line stand and won them the Lombardi Trophy in New Orleans.
Ellerbe, not Ray Lewis, also led the team in tackles in that contest, which should make him a huge priority for the Ravens' front office. Unfortunately, Baltimore is one of the most cash-strapped teams heading into 2013.
Key defenders Ed Reed, Paul Kruger and Cary Williams are all set to hit free agency,. The Ravens additionally need to address whether they keep Anquan Boldin and just how much they pay Super Bowl MVP quarterback Joe Flacco.
All those factors combined could result in Ellerbe being the odd man out despite his success. But, as documented by Jeff Schultz of the Atlanta Journal-Constitution, Ellerbe seems poised to rake in a big deal:
FWIW I spoke to Dannell Ellerbe Super Bowl week, mentioned #Falcons' possible interest. He smiled, said "Whoever offers the best contract"— Jeff Schultz (@JeffSchultzAJC) February 8, 2013
Although he may want to stay in Baltimore, there should be a long line of suitors prepared to offer Ellerbe big money.
Louis Delmas, FS
High-profile players both on the market and on his own team overshadow Delmas, making him something of a diamond in the rough. Delmas hasn't been diamond-solid in terms of health, though, missing a combined 13 games over the past two seasons with various knee ailments.
However, any team looking for a dependable free safety should give Delmas a long look. The focus will be on players like Reed and other Pro Bowlers like Buffalo Bills standout Jairus Byrd and the Niners' Dashon Goldson.
Delmas is a stellar all-around safety who is not exactly known for his ball-hawking capabilities, but nevertheless plays solid coverage and can pack a punch.
Lacking interception production is more of a testament to how bad the Detroit Lions' corners have been in recent years and Delmas' periodic absence from the field.
With a better supporting cast in the defensive backfield and a bit more of a stable franchise than the recent history the Lions have endured, Delmas could easily thrive in a new NFL environment and become a perennial Pro Bowler.