Practice Monday was a "get-back-to-football" day, as running back David Johnson described it, and the heavy work for this week's gameplan was still to come.

But it was still the first day on the field for Byron Leftwich, offensive coordinator.

"Byron said it (Monday) morning, 'We're not going to try and reinvent the wheel,'" wide receiver Christian Kirk said.

Leftwich, promoted Friday from quarterbacks coach when Mike McCoy was let go, is a bridge from the previous regime of Bruce Arians and, as noted by current coach Steve Wilks, someone who was around when the Cardinals had excellent success with Johnson as both a runner and receiver.

But just how much the offense will shift remains to be seen (Leftwich will address the media for the first time Thursday, during the regular press conferences for coordinators.)

"Our offense isn't going to change overnight because of what happened," guard Justin Pugh said. "We all played a role in what happened to coach McCoy, and it's not all his fault. There are things we have to correct, regardless of the offensive coordinator."

Wilks said he is looking for improvement from the offense and "that could mean a ton of things." But running the ball better – the Cardinals are last in the league in rushing, despite having Johnson – is the top priority. Protecting quarterback Josh Rosen is next.

The Cardinals have a lot to fix, of course. They are ahead of only the Bills in scoring per game, and remain last in third-down conversions.

Kirk said the plan is to find the core plays that the Cardinals do the best, to have a good base to turn to when they have to have a "good chunk" of yards. That could help with the third-down conversions and, with more first downs, actual sustained drives.

Using Johnson more as a receiver will help. Johnson said he didn't know exactly how his role might change from thus far this season, but Wilks did say one of Leftwich's attributes was his place as an intern on staff in 2016 when Johnson exploded for more than 2,000 yards from scrimmage.

"With 2016 being my best year, that's a good thing to hear," Johnson said with a smile.

Leftwich has a nine-game proving ground – although with a brutal road slate left for the Cards to play, in places like Kansas City, Atlanta, Green Bay and Seattle – in which to make it work.

"Byron wants to be great," tackle D.J. Humphries said. "He's not trying to hold anybody's place. He's not trying to be an interim. He's trying to be the guy. I can appreciate that."

ROSEN SITS OUT BUT IS EXPECTED WEDNESDAY

Rosen did not practice Monday because of his injured toe but he was out of the walking boot and Wilks said the quarterback should be back at practice Wednesday.

Pugh remained limited with the cast protecting his injured hand, while guards Mike Iupati (back) and Jeremy Vujnovich (hamstring), safety Tre Boston (shoulder/ribs) and cornerback Jamar Taylor (back) didn't practice. There is no official injury report until Wednesday.

MISSING BOSTON

Wilks said the absence of Boston was noticeable, particularly with a "busted play" when Emmanuel Sanders made his wide-open 64-yard touchdown catch. Safety Rudy Ford, playing deep centerfield on the play in place of Boston, moved way up during the play to create a hole for Sanders.

Wilks called the play unacceptable and that Ford was inconsistent, but said there was a lack of communication too often "not just with Rudy but with the other 10 guys."

Newcomer Eddie Pleasant figures to get a chance to play Sunday against San Francisco, if Boston remains out (which seems likely.)

"We need that kind of body back there, a physical guy that's smart, that can get lined up, that can learn this system quickly, and I think he can bring that," Wilks said.