Ohio State will need to replace some key contributors on defense in 2017. None loom larger than Raekwon McMillan's replacement at middle linebacker.
McMillan's ascent to middle linebacker since his arrival in 2014 was organic. He was a day-one contributor to the 2014 national championship squad as Curtis Grant's backup. Grant's departure after the season made McMillan the natural successor. He was arguably the focal point of the defense for the past two years.
The succession plan for 2017 is less obvious. There's no clear heir apparent like there was in 2015. McMillan's backup at the end of the 2016 season was Craig Fada, a walk-on and a graduated senior.