The foundation of the Detroit Lions' success in recent years has been built through the draft. General manager Brad Holmes and head coach Dan Campbell constantly profess to find players that "fit us", beyond the inherent talent for NFL-caliber draft prospects.
Campbell didn't last a decade as an NFL tight end because he was the most talented player or because he was incredibly productive (91 career receptions). He lasted that long because he embraced having to compete for a job and embrace a role every year. Coaches took notice of his grinder mentality, and he naturally seeks the same mentality in players he coaches now as part of a culture forged in competitive spirit and taking nothing for granted.