The best pick the Cardinals could have made would have been Von Miller, but he was off the board to the Broncos second overall.
Peterson has all the skills to be the next shutdown corner in the NFL. He is big for a corner, can run with anybody and can body up and play physical if need be. His return skills are also a bonus, and we will have to wait and see if the Cardinals use him in that spot.
The Cardinals had other needs more than cornerback, but couldn't pass on arguably the best player in the draft.
Bringing in new defensive coordinator Ray Horton means the Cardinals will put more pressure on the quarterback. That in turn will mean coverage outside will need to be tight, and Peterson can step in and help right away.
With Dominique Rodgers-Cromartie, Patrick Peterson and Adrian Wilson in the secondary the Cardinals should feel pretty good about the back end of their defense.
Many people may wonder why the Cardinals didn't take Blaine Gabbertt, and the answer must be that they didn't feel all that strongly in him.
Expect them to look to make a trade (when the new CBA is in place) for a veteran quarterback such as Kyle Orton, Kevin Kolb or Donovan Mcnabb.
Overall the Cardinals must feel good about this pick, and overall a grade of an A must be given to them.