Success in the National Football League is often reliant on compatibility between player and system.
When the 49ers hired Chip Kelly as head coach on Jan. 14, the conversation quickly turned to the potential resurrection of Colin Kaepernick's fading career because of that compatibility.
The system Kelly runs, in a lot of ways, seems tailor-made for Colin Kaepernick, enhancing his strengths as a player, while covering up some of his weaknesses.
The marriage already has defensive coordinators awake at night, terrified of the potential. Three rival defensive coordinators recently spoke with NFL.com's Albert Breer, providing comment on what the pairing of Kaepernick and Kelly could mean.