Detroit Free Press writer Dave Birkett is examining position groups in advance of this week’s NFL draft. Today, he looks at cornerbacks and safeties. Cornerbacks On the Lions' roster Chris Houston, Bill Bentley, Jonte Green, Chris Greenwood, Ronald Bartell, Conroy Black, Lionel Smith, Ross Weaver, Domonique Johnson. Safeties On the Lions' roster Louis Delmas, Glover Quin, Don Carey, Amari Spievey, John Wendling, Ricardo Silva, Tyrell Johnson. Lions' needs Houston and Delmas are back after testing the free-agent market and the Lions added Quin, one of the best available safeties, but they still have needs to patch in the secondary. At cornerback, Dee Milliner could be under consideration with the fifth pick. He’s an elite athlete who plays with the physicality the Lions like, but there are questions about his health after undergoing recent shoulder surgery. At safety, Delmas’ knee history can’t be overlooked, but Carey proved reliable in an expanded role last year. It wouldn’t be a surprise to see the Lions add through the draft at either position, and that’s after they took three corners (Bentley, Green and Greenwood) in Rounds 3-6 last year. Top 5 corner prospects 1. Dee Milliner, Alabama; 2. D.J. Hayden, Houston; 3. Xavier Rhodes, Florida State; 4. Jamar Taylor, Boise State; 5. Desmond Trufant, Washington. Top 5 safety prospects 1. Kenny Vaccaro, Texas; 2. Johnthan Banks, Mississippi State; 3. Eric Reid, LSU; 4. Matt Elam, Florida; 5. Jonathan Cyprien, Florida International.