Here’s what we know about the 2013 version of Oregon’s defensive line (Hart, Keliikipi, Heimuli, Armstead, Buckner):  the group is likely top-ten nationally. Here’s what we know about the 2013 version of Oregon’s defensive backfield (Ifo, Patterson, Mitchell, Hill, Jackson, Dargan):  the group is likely top-five nationally. Here’s what we know about the 2013 version of Oregon’s  middle linebacking group …