While projecting the second round of the NFL Draft is pretty much a fool's errand, it does give an indication of the type of players that could be available.
45 Dallas Kevin Zeitler OG Wisconsin Would be the top guard in the draft class in some years. If Dallas doesn't go DeCastro early, Zeitler fits here.
The early rounds have become a wasteland in the Jerry Jones regime, especially in regards to offensive linemen: Jacob Rogers and Stephen Peterman (2004), James Marten (2007), Robert Brewster (2008).
However, Wisconsin has a solid reputation for running a pro-style offense that churns out road-grading offensive linemen, and Zeitler, an athletic 6'4 315 guard, certainly seems like an excellent prospect.
Pro Football Weekly, who rates him No. 26 in the draft, breaks down his game: