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.

"You're wearing Lions gear, you've got to take care of the ball, or it's going to be hard to keep you around," Campbell said in his postgame press conference.

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