After seeing free agency, I don't think the Cowboys will draft DeCastro unless they are stuck at 14 and all their defensive line targets are gone. I think Coples, Cox, and Brockers will be rated high (by Dallas) and be rated close to DeCastro. Bucky Brooks (NFL.com) did a new mock and mocked Quinton Coples to Dallas at 14. I think a defensive lineman will probably fall to Dallas at 14, and even though it is a very risky position to draft in round 1, the Cowboys need a young, impact player in their defensive line, bad.
I think Mackenzy Bernadeau (26) projects to start at LG if all goes according to plan for the Cowboys. I think Bernadeau has more upside than Kyle Kosier ever had due to his added elements of power and size, and I think the Cowboys have high hopes for him, imo. I think he's a left side player and the pulling guard from the weak side.
On the other hand, I see Nate Livings as a short-term stop gap at RG, imo. As a result, I think the second round targets at guard should be Zeitler, Silatolu, and my favorite, Brandon Brooks. I think Zeitler and Brooks make a ton of sense, in round 2, because they are right side players. I don't think signing Livings would prevent the Cowboys from drafting Zeitler or Brooks in round 2. Bill Callahan was at Brandon Brooks' pro day according to SDogo, and Callahan has recently worked out both Wisconsin interior players according to SI.com (Tony Pauline). I think the Steelers would jump all over Brooks in round 2, and there are probably other teams, too. I think Dallas should be one of those teams. The Livings signing looks better, imo, if Zeitler or Brooks are drafted. That is where the interior value should be, I think. (pick 45 and at guard) However, teams in the late first could spoil it, because the Ravens and Packers need interior o-line help.
At center, Konz, Blake, and Ben Jones are probably the targets. If Konz is available in round 2, he has great value. However, I like Brandon Brooks better than all the centers. jmo
I think the Cowboys can for sure get a young, quality (plus) RG in the second round, but center is still a big question mark, imo.