Warren was drafted to be a NT, but they quickly learnt that he couldn't play that role and moved to DE. I think the same has happened to Brace.
I agree that part of the reason they drafted him was insurance incase they couldn't get Wilfork signed long term. But they still must have liked the player and he filled a need.
Drafting Brace and resigning Wilfork are unrelated. Do fans really think that BB only intends to have one NT on his roster at any given time? He has built a roster that is 60 players deep with starting caliber talent that runs to 8 defensive backs, 7 offensive linemen (8 now, with Mankins), 4 wideouts, 3 tight ends, etc etc. Why else horde all those draft picks if not to build a deep roster?
In any case, BB builds his front line with 300+ lbs bodies that are strong and can control gaps. The distinction between NT and DE in our scheme is really not as significant as it may seem. NT needs someone who can take on double blocks and power through trash. But, if you've got someone that can play the nose, that recipe can work at DE too, as demonstrated by the fact that Wilfork, Warren and Wright have all been rotating between NT and DE over the past few weeks.
I personally believe that if BB could play three NTs across his front three, he would. It's just that Nature doesn't provide the football world with enough 310-325# agile and strong athletes who have the right mental makeup to be professionals. If BB has a shot at another prospect or two with the physical and mental profile, I think he'll continue to add players opportunistically.
Lot of opinion on this board that we need to draft some more help for the DL, but frankly I'm pretty pleased with the group we have right now. Warren and Wilfork are blue chippers, but Wright has 4 straight games with a sack, Pryor makes his presence felt-- including knocking Favre under the chin, Deaderick has looked legit as a rookie starter, Brace flashes skills, including the 4th-and-goal stop of Adrian Peterson in Week 8.
I think Brace has work to do to learn how to be a professional's professional, but I chalk that up to immaturity. Hopefully he learns fast. He's got a good mentor in Wilfork.