I'd wonder just how much work is really needed on defense. Does it really need the overhaul that is being suggested in some places?
As a whole the defense really played great in 2006. The roster will need some reinforcements to play at the same level in 2007. Specifically at ILB and at CB if Samuel leaves.
Looking a little deeper I think it does need some improvement, not an overhaul but some additions to fortify the group.
I used two types of analysis (SEE DATA BELOW FOR DETAILS)
1) Key defensive statistics - Rushing YPG and Point Against.
---- a) Rushing - After week 9 the defense allowed 100 YPG rushing in 8 out of last 10 games
---- b) YPG - Not as bad but still trended in the wrong direction, after week 13 allowed 20 PPG in 6 out the last 8 games. Only allowed one game over 20 before week 13.
2) Eyeball test & Roster analysis
---- a) The play at LB really slipped when Seau went down. Vrabel, Colvin and Bruschi all switched positions. You can make a case that all the movement made the Patriots worse at every LB position.
---- b) Bruschi was not a play maker in 2006.
---- c) Only 6 Signed LBs (assumes ERFAs and tendered) - Colvin, Vrabel, Bruschi, Woods, Mays, Alexander. 6 players signed leaves a need to fill 3-4 spots just to complete the roster. 1 must be starting caliber at ILB and 1-2 must be high level backups (TBC level or higher).
---- d) CB - Samuel - Stays secondary is ok, if he leaves there is a big void.