Ok, so waht do we know about our defense:
1) Clancy Pendergast is the DC
2) They split up the groups differently in camp -- Hali and McBride were working at outside linebacker.
3) They have not traded Dorsey
4) Tank Tyler calims he will play nose, and Dorsey will still be a three technique
5) We took two five technique ends to begin the draft
The reasonable conclusion: we are not playing a pure 3-4. We are playing the 4-3 under defense with ome 3-4 looks in it. We knew this already, but few pay attention.
Dorsey fits in the 4-3 under. It shifts the line to the left side of the offensive line with small penetrators, but then asks guys to be stout against the run on the right side.
The DL has a 5 tech on the right tackle, a nose that takes on the right guard and center, a 3 tech that penetrates against the left guard, and a standing end/linebacker hybrid to take on the left tackle. Take a look at the diagrams in one of the recommended fanposts on the 4-3 under. In this defense, the line will look like this:
Jackson and McGee -- 5 tech
Tyler and Edwards -- Shaded nose tackle
Dorsey and Boone -- 3 tech
Vrabel and ??? (I think they had Brian Johnston and Studebaker also in this rotation) -- Standing End (the Joker)
This scheme also makes good use of the linebacker talent that we have. You have a Sam backer that lines up on the outside of the TE to take on the run and to rush (from the right side of the OL). They have Hali and McBride lined up here. This person is a LB, but needs to be really stout like a DE. Both of these guys were used in coverage during zone blitzes last year and could perform limited coverage.
They have a traditional MLB that needs to be really stout at the point of attack. They sometimes have to take on the right guard and to stop the run. Clearly this is Zach Thomas' job.
The Will backer is also a hybrid MLB, since the look put 5 players on the line most of the time. This linebacker needs to be versatile to cover the left side, but is also free to make plays and to rush the QB often. Derrick Johnson and the guy we got from Atlanta last year will work here.
The safeties will have some cover responsibilities, but the SS can come down into the box more. We have the perfect set for this. The CBs are also good, but we will be playing some more man coverage, so the athletic CB from OSU (Washington) makes a lot of sense.
What do we still need? A guy to play behind Zach Thomas (I want Scott McKillop). I also have not been able to fit Darrell Robertson into the scheme so far (perhaps a backup to Tamba). I also think McBride might be one of the worst fitts for the scheme, but I don't know. Don't be surprised if we move him later this year for a mid-rounder next year.
Anyway, this is why it looks like we are going to a 3-4 and yet still have not traded our 4-3 guys, at least IMHO.