Finally the head coach of the Patriots seem to realize what Coach LeBeau and the Pittsburgh Steelers have always known and that is to run a 3-4 defense you need line backers. The Patriots LB core is pure garbage with LB Jerod Mayo being the best player and he is vastly over-rated. After coming to this realization the Patriots seem to have decided to take the 4-3 defensive motto which is you can never have too many defensive linemen. They first traded for Albert Haynesworth as a "pass rusher" in Bill's word. Since no D-linemen is a pass rusher in the 3-4 this was the first clue to the change.
Bill Belichick has always been the best judge of his roster. He consistently uses his player in ways that highlight their strengths and hide the deficiencies. Lets face it that team has a defense that seems to always be in the top ten rankings yet it is filled with role players a sub par left overs.
Haynesworth numbers with Tennessee would be further motivation.
In 8 seasons in a 4-3 system (7 with Tennessee one with Washington) he has 308 tackles (38.5 a year) 28 sacks (avg 3.5 a year) 46 stuffs (5.75 a year). Where '07 and '08 was his prime having 14.5 sacks in two years.
Andre Carter in 9 years of playing in the 4-3 has 63.5 sacks (average ~7 a year) and 398 tackles (~44 a year)
Shaun Ellis in 9 years of the 4-3 had 463 tackles (~51 a year) and 61.5 sacks (~6.8 a year)
In a interview Bill said this about Carter..
"He's had a lot of production throughout his career. Last year, when Washington went to the 3-4 defense, it wasn't a good fit for him evidently in that system. But we feel like with what we'll be asking him to do this year - relative to what he was asked to do last year, what we've seen him do in the first nine years of his career - that we can use his ability on the edge and he can be effective."
They also sign back DL Gerald Warren and were very interest in signing former Bears DT Tommy Harris.
Belichick also said "I think how we align and how we handle the responsibilities, I think that could definitely change by game plan or by what we feel are our strengths and weaknesses and how to best deploy the players." Though he denied change entire philosophy.
All these moves make me believe Bill has given up the 3-4 to go to the 4-3 which should keep Mayo clean and able to play to his potential and provides a pass rush that they didn't get last year. At least they may be 1 year away from a total switch to the 4-3.