The Cowboys continue focusing on the offensive line. They went offensive tackle in the first round last year in Tyron Smith and again hit the offensive line this year with David DeCastro in the first round. Now they move to the defensive line.
SB Nation's Cowboys blog, Blogging The Boys, explains the pick:
After picking the premiere guard in the draft in round one, David DeCastro, the Cowboys were initially looking at shoring up a troublesome secondary in round two. But, much to their delight, borderline first-round talent Nick Perry from USC was still on the board, and fits a need for Dallas. Although listed above as a defensive end, Perry's size is more suited for an outside linebacker in the Cowboys 3-4 defensive scheme. Dallas franchised current strong-side linebacker Anthony Spencer for 2012, but has yet to work out a long-term deal. Spencer's strength has always been against the run, and the Cowboys are looking for a pass-rushing bookend to superstar DeMarcus Ware. Perry's best attribute in all of the scout's eyes is his ability to rush the passer.
Perry has expressed a preference for being a hand-on-the-ground defensive end and Dallas will be able to use him in that way and as a stand-up edge rusher. Contrary to popular belief, the Cowboys use multiple defensive fronts, switching into a 4-3 alignment for a good percentage of plays. Perry can be used as a pass-rushing defensive end in that alignment, and platoon with Spencer in a base 3-4 alignment. Spencer is stronger against the run, Perry shows much more skill as a pass rusher. Dallas will have to work with Perry to develop his skills as a full-time 3-4 OLB, mainly in setting the edge against the run and dropping back into coverage on occasion. These are the areas that make the pick a bit of a risk. But the benefits of getting an athletic pass-rusher who has been graded by many as a first-round talent is too much to pass on. For too long teams have overloaded their protections to stop Ware; having a legitimate pass-rush option opposite him could greatly benefit the Cowboys defense, and may even help out a secondary that has struggled.