Malcom Brown has had a few snaps I'm sure he would like back, particularly against the run but other than that he's looked the part to me. Aside from QB I believe that DT is the second hardest position to adapt to in the pros. College interior OL range from "I could go Pro" to "I'm just here to hit the books, man." It's a HUGE leap for a DT to make and that's not even taking into consideration the various other intracacies that get introduced to the DT position once you make it to the NFL.