Musts are called musts for a reason. Getting there took a little while, but the Saints have been dead set on adding a cornerback all offseason. After missing out on a draft-day trade and nothing materializing in free agency, New Orleans finally filled the void by trading for Houston Texans cornerback Bradley Roby. The deal brings a known commodity with a track record of success to the spot opposite Marshon Lattimore and shores up one of the biggest questions remaining on the roster. But Roby doesn't just plug a gap. His skills should translate well to the things the Saints like to do on defense.