When you're looking at rookie defensive backs from a fantasy perspective, you (naturally) want rookies who will be starting immediately. But you also want rookies who will be playing in the secondary next to experienced defenders. Preferably next to defensive stars. Offenses will always try to exploit the weakest part of the defense, and in most cases the weakest part is that newly-arrived rookie.
LaRon Landry (Washington, 6th overall) - Case in point is Mr. LaRon Landry. He'll be playing safety in a revamped secondary next to veteran cornerbacks Fred Smoot and David Macklin and superstar safety Sean Taylor. Do you think Tony Romo wants any part of Sean Taylor when he can target Landry? Expect Landry to roll up big tackle totals this season. He will probably be worth starting in larger IDP leagues.
Reggie Nelson (Jacksonville, 21st overall) - Nelson is another guy who steps into a starting safety position. With fantasy stud Rashean Mathis at cornerback, Nelson should be in the cross hairs of the opposing quarterback every game. He could be worth a bye-week spot on your team.
Chris Houston (Atlanta, 41st overall) - Normally you want to draft safeties for the DB slots on your fantasy team, but Houston may be the exception. With DeAngelo Hall playing cornerback on the left side, expect to see quarterbacks aiming for the rookie on the right side. Houston's impact may be reduced because the Atlanta safeties (Chris Crocker, Lawyer Milloy and Jimmy Williams) aren't that great either, but he is still the weakest part of a weak secondary.