David Johnson said he didn't need much work in the preseason, if any.

Then the running back showed why in Saturday night's preseason opening 24-17 win over the Chargers at University of Phoenix Stadium, ripping off a pair of 14-yard runs before being quickly shut down for the game.

It set up a two-yard touchdown run on the opening drive by rookie Chase Edmonds, and helped set the exact offensive tone coach Steve Wilks wanted.

" 'Three-One' sets the tone," Edmonds said. "It was cool to finally see him let loose. They take care of him in camp so you don't get to see him really let loose and he let loose right with those 14-yard runs. We feed off of him."

Johnson missed almost all of last season with a wrist injury. Against the Chargers he looked like the all-pro he had been in 2016. There's a reason Wilks wants to ride the running game.

Quarterback Sam Bradford only threw one pass in his one drive of work. The other seven plays were all runs.

Wilks all but announced the Cardinals would stay on the ground at the end, using a jumbo package with no wide receivers on third-and-goal from the 2-yard line, and then, after Edmonds was stuffed, running basically the same play again.

"We wanted to establish the run, which we did, and as I said earlier in the week, if we had an opportunity, we wanted to be aggressive and we did on fourth down," Wilks said.

Edmonds was stuffed on fourth down, but somehow managed to keep churning forward without hitting the ground, aided in part because he fell on top of center Mason Cole as he reached for the end zone.

"Coach Kirby (Wilson) always talks about, with goal-line running, whatever the blocking is, it could be clogged, goal-line running should be about the pride of the runner," Edmonds said. "Find a way to find that white line."

CASH GETS BIG PLAY, THEN SUFFERS HARSH INJURY

Linebacker Jeremy Cash has had a solid training camp and brought that into the preseason opener, making a couple of tackles and returning a fumble 12 yards for a touchdown.

But that joy turned quickly when Cash hurt his right knee making a tackle later in the game, bad enough that he had to be carted to the locker room. Wilks said there wouldn't be an update until Monday, but if it is serious, it'd be another blow to a linebacker corps that's been banged up and certainly to Cash's quest to make the roster.

"Definitely prayers go out to him," linebacker Haason Reddick said. "He had a couple of great plays tonight. Unfortunately with whatever might have happened to him. It's got to be the 'next man up' mentality in this league. Someone else is going to have to step up."

The Cardinals already had minor injuries sidelining linebackers Deone Bucannon, Josh Bynes and Airius Moore.

KIRK'S NEAR MISS ON HIS FIRST TOUCH

Rookie Christian Kirk, playing his first NFL game in his hometown, almost made it unforgettable. The first time he touched the ball – on a first-quarter punt return – he raced 38 yards and looked like he was headed for a touchdown. All he had was the punter to beat – and he slipped and fell.

"I got a bit excited," Kirk said. "I'm sure I'm going to hear about it over the next week."

The return did set up the Cards' initial TD drive. Kirk admitted he had flashbacks to college, when he returned the first punt he caught at Texas A&M for a score.

"I'm sure we'll be able to get one in the season," Kirk said.

LEADING-WITH-HELMET RULE TAKES CENTER STAGE

The NFL's new rule against initiating any contact with the crown of the helmet was on display Saturday, with it drawing flags four different times.

"Some of those looked iffy, man," Reddick said. "We'll see what the league does about that.

"It does worry me because I know I saw one that was a great, fit-up, form tackle and I didn't understand why that was a penalty. We'll see what happens."

Preseason games often have a lot of penalties, but it didn't make the 26 total accepted penalties – 15 by Los Angeles, 11 by the Cardinals – any easier to digest.