Draft Lab: Talking about linemen

As the NFL draft gets closer we'll spend plenty of time discussing offensive and defensive line prospects. The Minnesota Vikings have an obvious need for a left tackle. The Detroit Lions need a succession plan for left tackle Jeff Backus, and the Green Bay Packers need pass-rush help at either defensive end or a linebacker. This edition of ESPN's "Draft Lab," featuring Mel Kiper Jr. and Todd McShay, offers specific possibilities on all three counts.