Larry Johnson and Greg Mattison have a combined age of 136 years. They have been FBS coaches for a combined 63 seasons. Mattison has been a coordinator in both major college football (including at Florida, where he won a championship with Urban Meyer) and the NFL, while Johnson is widely regarded as one of the best defensive line coaches (if not the single best) in the game.
This is why they are two of the most key people (players included) for Ohio State as the young Buckeyes are about to begin spring practice to open the 2019 season.