When the 2013 Philadelphia Eagles became only the second team in NFL history to rack up 1,000 or more passing yards and 750 or more rushing yards in the first four games of a season, it seemed as if Chip Kelly's offense was on pace to be a potentially record-setting platoon.
Things certainly haven't seemed that way since, especially over the past two contests, when the Eagles failed to score an offensive touchdown and averaged less than 4 yards per offensive play in each game.
This latter performance has brought about the question of whether the blame for this collapse should fall on the coaches or the players.
The answer to that query can be found in the metrics and game tapes, both college and pro, from the past few years. And they emphatically say that, while there is some fault to be found on both sides, Kelly inherited a personnel situation that was badly out of alignment with both his game-management and play-calling systems.
A good place to start illustrating this point is a short review of the system that made Kelly so successful during his head-coaching tenure at Oregon from 2009 to 2012.