Diaco said the players didn't like it and, what's more, had forgotten how to tackle because of it. He also said he'd heard the change to the Atavus system tied back to a mandate from NU's administration — someone above coach Mike Riley.

"Which didn’t sound like anybody believed in," Diaco said. "So the tackling degenerated. So when you think about it — you think about a player showing up here who’s a really great tackler and then becomes a worse tackler? That doesn’t make any sense.

"So I had no idea until we went to our tackling drill in the first full practice of spring football and found that the players were spectacularly frustrated during the drill, because they’re willing, they’re talented enough to tackle, they’re tough enough to tackle, they’re willing tacklers, they want to do well, but they don’t fundamentally know, anymore, how to tackle. At all. So we’ve been working hard at just that one thing."

Nebraska's 2016 defensive coordinator, Mark Banker, disagreed.

"He's full of it," Banker said. "He's making excuses. It was not mandated by the administration — not to my knowledge — it was suggested and then it was put forward by our head coach to bring that company in, and then we used that method."