Ty Warren played a handful of snaps in the season opener last season before being put on IR and replaced by Sealver Siliga. Justin Bannan was not resigned, and Derek Wolfe looks to mainly be a DE in 2013 though he should still see some snaps on the inside in sub packages.
That leaves a core group of Vickerson, Knighton, Williams, Unrein, and Siliga.
Both Vickerson and Knighton figure to be the starters. Both are similar players with similar output. They are also both capable of playing the UT and NT roles on base downs. Both figure to plug up the middle of that line making it difficult for teams to run. They can both also push the pocket a bit from the interior. In spot duty both combined for 4 sacks last season (tired of the word "both" yet?)
Sylvester Williams is by far the most intriguing piece of the puzzle. This man has interior pass rush specialist written all over him. The first step of his off the snap is faster than anyone else on that line except for Von Miller. I think he has the frame to add some weight, but for now, his athleticism is something the other players don't quite have. Big Vick can move for a big man, but Williams is on a different level. If he can quickly process the mental aspects of his game and build a solid foundation of fundamental techniques, he can easily be an impact player in 2013. Will he play a ton of snaps? Remains to be seen, Wolfe did as a rookie. Seems to be expected of most high draft picks in the Elway regime. He will affect the game from the middle regardless of how much time he sees, guaranteed.
Mitch Unrein surprised me a little bit. He's quicker and athletic which is why the Broncos used him in the nickel defense as a 3-tech, but he's also strong enough to hold the point of attack as a 0 or 1 tech. I seriously doubt Siliga will challenge Unrein for that penultimate spot in the DT rotation.
All in all, we have two big bodies that can push the pocket and clog the run, one potential pass rushing monster, and one good rotational backup.