From the FanPosts. Had to Google to get the title.  -Joel

This FanPost started as a reply to hmills' excellent comment here. He wrote,

Running nickel behind Hali-Dorsey-Smith/Edwards-Jackson-Sheffield would look at LOT like the nickel that KC used to run in the early-to-mid ’90s, to very good effect. Personnel groupings like that leave KC with just one ILB on the field.

Yes, it certainly does and that helps us tremendously.  Most of us would agree that inside linebacker was one of our biggest weaknesses on defense last season.  It always seemed that if we somehow stopped (or rather limited) the inside run on first down, we'd give up the shallow curl or the quick slant on 2nd down.  Although we have some inside linebackers who are solid to fantastic in some areas, we lack a complete inside linebacker.

Corey Mays. Demorrio Williams, Derrick Johnson, and even Jovan Belcher all have some of the qualities of an ILB, but none of them have all (or even most) of the things you look for in a 3-4 inside linebacker.  Mays is fairly solid on inside runs (especially if he's assigned to one gap on a run blitz), but hesitates and often gets beat when he has to read two gaps our pursue to the outside.  Williams and Belcher have good lateral speed and are solid tacklers, but are somewhat a liability in pass coverage.  Williams especially seems to lack that sense of which receivers are about to enter his zone.  And finally, we come to DJ, who apparently lacks the size (will? strength?) to take on the guard and be successful on inside runs, but has fantastic pursuit speed and is extremely solid in pass coverage.  We can talk about his inconsistency all day, but I think DJ is one of the rangiest LB's I've seen in the NFL.  There are nickel backs who get beaten down the seam by Antonio Gates, but I can think of dozens of times when DJ has been in excellent position when RIvers is looking to throw.

Last season, teams took advantage of the incompleteness of our ILB's.  If Mays and Williams were in, we were vulnerable down the seam (especially on the side away from the less slow safety), because they are both slow at dropping into coverage (don't even talk to me about how bad it is if they bite on the play action fake).  If Mays was on the sidelines, then an inside trap was golden as the linemen swatted Williams or DJ out of the way.  Running a nickel allows us to tailor who that one ILB is to the responsibility of the ILB in that play or a small series of plays. and replace the other ILB with a DB who has a broader skillset.  Assuming the offense is in a 3WR set, let's discuss some of the possibilities.

Let's start with Arenas at Nickel and Berry and Page/Morgan(or whoever else pulls their head out of their arse) at safety.  Williams at ILB...I think this may be the base set.  Williams is only average in a few areas but really doesn't have a glaring weakness - he can moderately defend the inside or outside run.  Based on his performance in the SEC,  Arenas should be solid in run support and in coverage (actually, Arenas is the player who intrigues/excites me the most...I have a feeling he is going to be spectacular - he seems to have it all put together)

But what about DJ at inside LB, Berry at nickel back, and Page and Lewis at safety?  Now your third cornerback played some weakside linebacker last season, but can also cover awfully well.  Or call a run blitz and send flowers and Berry with Vrabel and DJ dropping into coverage?  On 3rd and long send Mays or DJ on an inside blitz with Arenas, Berry, and Lewis in a 3 deep zone. 

The numerous options are starting to sound good as we can protect ourselves from the weakness of any one inside linebacker.