Detroit is breaking in new play callers on each side of the ball. In terms of those operations, particularly on offense, with new coordinator John Morton -- from flow of the game to getting plays in swiftly -- Campbell said it went better than he expected out of the gate. However, the struggles between the whistles overshadowed any positives.

He saw it, saw the defense, audibled on his own, which was outstanding. So that was promising," Campbell said of Hooker.

Detroit Lions head coach Dan Campbell sends a warning to his team after their sloppy showing in the Hall of Fame Game.