The point of this post is to create a place in which to focus a discussion of the 49ers' defense, including formations and player utilization, as well as the performance, talent  and  "shelf-life" issues of current players. I will start with a quick summary and some questions, and then just let the discussion go forward. (Player ages are in parentheses.)

Down lineman:
Sopoaga (28, Hawaii)
Franklin (29, Tennessee
Justin Smith (30, Missouri)

not starting in base:
Balmer (23), Jean-Francoise (23), McDonald (25),  Evans (29) and Ahmad Brooks (25) (who is large OLB /small DE type (260 lbs)).

Linebackers:
Lawson (25)
Spikes (32)
Willis (24)
Haralson (25)

Additional line-backers include:
Wilhelm (28) and Mckillop (23) (inside), and Briggs (24) and Brooks (25) (outside).

Current base-defense secondary:
Bly (32)
Spencer (27)
Lewis (29)
Goldson (25)

nickle back:
Brown (24)

I would be interested to get a better understanding of: 1) how much playing time various players are getting (e.g., Balmer, Francoise, Brooks, Francoise, Mckillop, etc.), 2) what players being used in non-base defenses and situations? (and who is being subbed into base),  3)  how well particular players seem to be playing and progressing, etc. 

Also feel free to post analysis of formations and personnel in nickel and dime defenses.

Any analysis of defensive alignments and tactics, and their implementation with the current 49er roster, is welcome.