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49ers Defensive Personnel: 3-4 vs. 4-3 Scheme

The 49ers defense has struggled at times this year and certainly has not lived up to their own Top-Five expectations...nor most of the fans' expectations either.  Some call it a product of seems like everything is wrong at times, doesn't it?  Or is the defense really struggling that mightily?

The pass rush has been abysmal at times, registering most sacks after at least three or four seconds have ticked off since the snap.  This puts pressure on the coverage and defensive backs who are not known as elite players by any means.  That's not a dig on the 49ers secondary, but let's be's not like Darelle Revis and Namdi Asomugha are our corners.

This has caused many, myself included at times, to question whether the problem is perhaps one of scheme rather than talent.  Rushing just three defensive linemen while in base 3-4 defense (and not blitzing) doesn't seem to generate sufficient pressure on those first and second down pass plays.  The outside linebackers were mostly 4-3 defensive ends in college and often struggle to run in space with speedy backs on edge runs or screen plays.

It's no secret that the season hasn't started off with a bang.  I think we all know it's at least a remote possibility that a new coaching staff could be in place at sometime during the off-season.  It's also quite possible a new Defensive Coordinator may be in favor of a switch to the 4-3 defense.

So how do the players who are on the roster translate from one scheme to the other?  After the jump I'll put together a 4-3 defensive scheme using only existing players and give some brief reasons why I put specific players in the positions I did.

4-3 Defensive Line

  • Starters: Ahmad Brooks - Isaac Sopoaga - Aubrayo Franklin - Justin Smith
  • Rotation/Backups: Travis LaBoy - Ray McDonald - Ricky Jean-Francois - Demetric Evans

Most of these guys play in these positions on Nickel defense it's not really anything new for them.  The biggest difference is that Sopoaga and Franklin are not in on Nickel, so they would have to get some practice at true 4-3 DT but as big gap-pluggers in the 3-4 I don't think this would be a major issue.

Travis LaBoy was a 4-3 DE and has not yet developed much beyond a pass rusher. My point being that we're not losing much in terms of a LB converting to DE.  Brooks is much the same in that he's still primarily been a pass rusher and not played many snaps at OLB where he played the run or covered passes.  Still I have a slight hesitation in pegging him a DE because he played inside linebacker in college in a he could be valuable as depth there.


4-3 Linebackers

  • Starters: NaVorro Bowman - Patrick Willis - Manny Lawson
  • Rotation/Backups: Parys Haralson - Takeo Spikes - Keaton Kristick/??

Bowman played outside in a 4-3 at Linebacker U (Penn State) so I have little doubt he could handle that role.  Lawson is used to playing the weak side and is one of the better pass defenders on the team, so I think he stands up as a LB rather than dropping down to DE.  Do we even need to cover Willis and Spikes?  Didn't think so.  Haralson could take Bowman for the WLB spot or provide rotation and backup duty.

The depth at LB is my only real concern.  As I mentioned Brooks could be a wild-card...are there any 4-3 teams you guys know about that use a DE as a LB at times too?  Because I could see Brooks doing that with his skillset. 

Kristick is not a guy you hope plays a lot right away and chances are there would need to be a draft pick or acquisition made to shore up the backup SLB position.

Obviously there are going to be a few players here who will be cut, leave for Free Agency, or possibly injured or traded...but you get the picture.  So what are your thoughts on switching to the 4-3 with the current defensive personnel?