Perdue, and guinn, were top lineman, they could have played linebacker. there speed and quick feet along with great hip flexibility, set them apart from the other lineman, Wil Odom, was the same way. Now I think theres two or three more lineman I saw with big time potential,but one of the biggest keys in getting better at playing Defense on the line, is developing quick feet, and the same approach should be tooken, when playing Offensive line, you got to be able to get over and make that block, being big in the 7th , 8th , and 9th , you got away with just size alone, Now other teams line up with smaller and quicker guys that could care less about your size. So just alittle time here and there on foot speed drills, would help out alot.