Gregg Rosenthal delved into the 20 most important skill position competitions on Wednesday. Here I examine the top 15 battles at Individual Defensive Player (IDP) positions.

For IDP newcomers, I wrote a column in our 2008 Rotoworld Fantasy Draft Guide that provides a rundown of each position in a 3-4 and 4-3 defense and how productive players in those roles tend to be. If you're already a subscriber or in the process of becoming one, check it out and let me know if it helps.

The Draft Guide contains rankings of the top 83 linebackers (LBs), 73 defensive linemen (DLs), and 100 defensive backs (DBs). Scott Morrow penned an Undervalued IDPs column and Rosenthal a Rookie Ranks article. As you can see, the guide contains an abundance of worthwhile content.

Getting to know defensive players is a useful way to understand how certain teams' defenses work. It can benefit fantasy leaguers on the other side of the ball as well. Increasing your basic player-by-player knowledge allows you to become a more informed fan and a dominant fantasy owner.

1. Broncos Middle Linebacker

Competitors: Nate Webster, Niko Koutouvides

Denver signed Koutouvides, Lofa Tatupu's old backup in Seattle, to a $7.5 million contract in March and penciled him in as D.J. Williams' replacement inside. That lit an apparent fire under Webster, who's been so impressive in offseason workouts that the race is now dead even. Webster has the advantages of superior athleticism and experience in Denver's scheme, while Koutouvides would likely be more stout versus the run, a weakness for the Broncos last year. Williams posted an AFC-best 141 tackles in the middle in 2007, so it is a hotspot for production.

2. Lions Middle Linebacker

Competitors: Paris Lenon, Jordon Dizon

The incumbent, Lenon opened camp as the clear leader and gained some separation when Dizon held out a few days. Detroit's second-round pick, Dizon has the speed and instincts that make him a strong fit in Rod Marinelli's Tampa 2. However, middle linebacker in that scheme is not an easy position to play and Lenon knows what it entails. The loser will likely start at strong-side linebacker, a much less tackle-friendly position. The winner could challenge WLB Ernie Sims for the Lions' tackle lead. There is a chance that Lenon will start in Week 1 and give way to Dizon after a few games.

3. Chiefs Middle Linebacker

Competitors: Donnie Edwards, Napoleon Harris, Pat Thomas

You wouldn't know it by his totals (116 tackles, 2 sacks), but Harris busted as the Chiefs' MIKE in 2007. Imagine how many stops he would've made if he was a good player. Edwards is 35, but can still move and bag ball carriers. Our money is on him ending up as the starter because he is a playmaker and Herm Edwards wants his middle 'backer to create takeaways. But Thomas, a journeyman special teamer, has shockingly taken the early lead. Edwards is currently stationed on the weak side, ahead of slow starting free agent signee Demorrio Williams.

4. Lions Strong Safety

Competitors: Daniel Bullocks, Gerald Alexander, Kalvin Pearson

Bullocks was supposed to have grasped this job by now, but has been extremely slow to recover from the ACL he tore nearly a year ago. He has not practiced yet in camp. Alexander, Detroit's starting free safety last season, is a better cover player but not the ballhawk Bullocks can be. Pearson is a career special teamer. The Lions' front seven is among the league's least talented, so tons of opposing ball carriers should get into their secondary all season. If one can control this job, he could lead the NFL in tackles by a defensive back. There's no frontrunner yet.

5. Browns Right Cornerback

Competitors: Brandon McDonald, Terry Cousin

McDonald showed he can play in spot duty last year and has been with the first team opposite Eric Wright all offseason. But Cousin is a savvy vet and won't give up easily. The Browns were also in the hunt to acquire Fabian Washington on draft weekend (he ultimately went to the rival Ravens), so a trade could still be made (Lito Sheppard, Ashton Youboty?). But for now, McDonald appears to be locked in. A former wide receiver, McDonald has terrific ball skills and is a willing tackler. If he solidifies the position, he'll be a solid DB2/3 target.

6. Jaguars Weak-Side Linebacker

Competitors: Daryl Smith, Justin Durant, Clint Ingram

This battle is really Durant against himself. Ingram is a strong-side player and Smith can play all three positions. Durant is a shade small, but has spectacular athleticism and packs an explosive punch. The second-year linebacker began camp as Jacksonville's starter on the weak side. If he stays there, Ingram will likely be first off the bench with Smith at SAM and Mike Peterson in the middle. Durant could get 100 tackles as a 16-game starter at this position.

7. Buccaneers Left Defensive End

Competitors: Marques Douglas, Kevin Carter, Greg White

At about 300 pounds apiece, Douglas and Carter are the best run players of this group, but White possesses rare pass-rushing and open-field hitting ability. He led all NFL defensive linemen in forced fumbles (7) and recorded eight sacks despite being a rotational piece in 2007. White is also playing for a contract. Carter is currently getting the most first-team reps, but perhaps only because he is an early-down force. Even if White doesn't "win" the competition, he should play the most snaps overall. If White does pass Carter, he'd have top-15 DL potential.

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