This is a guest pick from Tre9er, one of the front page writers at Niners Nation and frequent abuser of Twitter's abilities to re-tweet the opinions of others to his followers. You can follow him @Tre9er.
Ideally the Cardinals wanted to be sitting here deciding between Blaine Gabbert and Von Miller, both representing top talent at each of the team's two greatest needs. Not a bad consolation prize picking up Peterson here, though.
Fifth overall is about as early as you want to take a cornerback, but Peterson is one of the best CB prospects to come along in a very long time and is well worth the pick. The selection gives Arizona a blanket secondary, as well as adds a physical element to not only the coverage of the NFC's notoriously large, strong receivers, but also in the run game. Peterson is the size of a large safety but runs, turns, and makes plays like a corner. He likes to mix it up against the run, too, which benefits the Cardinals playing in a division known for thumper running backs. If they so choose, Peterson is a great return man too and can add another potential method of scoring points and gaining field position.
While they still need to upgrade their pass rush, Peterson makes it instantly look better by being able to take away half of the field on passing downs, giving the men up front more time to reach the quarterback. This draft features a deep crop of 3-4 OLB prospects and there is no doubt the Cards can find someone in the second or third round to replace Joey Porter and/or Clark Haggans. Some options include Jabaal Sheard, Justin Houston, Dontay Moch and Akeem Ayers. One of these players is bound to be available to Arizona with the 38th overall pick.
Much like the draft is deep in pass rushers, it's also relatively deep in quarterbacks. Second and third round options such as Christian Ponder, Andy Dalton, Colin Kaepernick, and Ricky Stanzi are considered guys who could play on Sundays if given varying amounts of time to develop. Ponder is largely considered to be the most "pro-ready" QB in the draft and is also a consideration with the 38th pick. Of course, if free agency ever does arrive, the Cards could potentially make a play for Donovan McNabb, Carson Palmer, Chad Pennington, or another veteran signal-caller.
All-in-all this seems to be a safe pick that will pay immediate dividends for the Cardinals.