The priorities, Wilks said, are to get Rosen in better positions to succeed – including tweaking pass protections for more maximum blockers and using him on play-action and bootlegs – and most importantly, getting running back David Johnson back into a starring role both in the running and passing games.

That's why the hiring of Leftwich could help – Leftwich was a coaching intern in the 2016 season in which Johnson exploded with more than 2,000 yards from scrimmage rushing and receiving.

"With Byron being here before and being a part of that and understanding the success (Johnson) has had in the past, hopefully we can tap into that," Wilks said.

Leftwich, the 2003 first-round pick of Jacksonville who played nine seasons in the NFL, was brought in by former coach Bruce Arians for that internship in 2016 and was promoted to quarterbacks coach in 2017. Arians also let Leftwich call plays in a couple of 2017 preseason games, so he does have some experience in that area.

"I'm a pretty confident guy, but I had never done it, and I had never practiced it," Leftwich said in February. "That's the tough part. Knowing B.A., B.A. ain't going to give you two weeks in practice to prepare. He gave me a 10-play period to call them. The first time I ever called plays was in the game. I wish I would have done a few things here and there better, but that's the exciting part of growing in this business. That helped my growth."

When Wilks was hired, he kept Leftwich on staff as quarterbacks coach.

The playbook and scheme aren't changing, Wilks said. How it is deployed will be. As quarterbacks coach, Leftwich already had some input on what to use.