When Arizona took the field for its season opener against NAU, something felt wrong. The Wildcats offense, albeit explosive with Daniel Jenkins as the starting running back, was missing a rumbling roar.

That roar was returning All-American running back Ka’Deem Carey. And now, with him back on the field, Arizona’s offense is progressively becoming one of the most potent offenses in the country.

“We call us thunder and lighting,” Carey said, referring to himself and Jenkins. “I’m thunder, he’s lighting. I come with the boom, he comes with the speed. [Defenses] can’t really key [on either one of us].”

The nation’s rushing leader from 2012, Carey returned for his junior, and possibly final season in Tucson with high hopes. After rushing for 1,929 yards in 2012, Carey made it clear that anything short of 2,000 in 2013 would not be acceptable — a jump no former nation’s leading rusher had ever accomplished before. And missing the season opener with a suspension makes it even harder.

But there’s no denying the effect he’s had on the entire offense since returning in week two at UNLV.

Despite getting fewer reps during fall practice and not being at top football shape yet, Carey has rushed for 299 yards in two games and scored four touchdowns.

“We’re out there balling,” Carey said after Saturday’s game. “And I’m getting to rolling and getting the cob webs off of me — and I love it.”

From Carey’s reaction, it’s clear that he doesn’t feel he’s hit his stride yet and that we should expect more from him as the season progresses. Last year, Carey had some of his bigger games toward the second half of the season.

Saturday against UTSA, the Roadrunners’ defense stacked the line of scrimmage, putting at least eight defenders in box trying to make sure Carey wasn’t the guy who beat them. UTSA contained Carey early, but then couldn’t stop the Wildcats’ passing.

Once the Roadrunners had for the most part given into Arizona’s speed, Carey was allowed to run for 128 yards and score two touchdowns. Carey’s tough running ability is a perfect match with the speed of Jenkins and the quick tempo of the offense.

As the season progresses, expect to see not just more from Carey but also more from the passing game as it slowly opens up. Much of senior quarterback B.J. Denker’s improvement over the past three games has been intertwined with the success of the running game.

There has been a clear, gradual increase in Denker’s production from week to week, and it started with the addition of Carey into the lineup. Saturday night, Denker had his best game of his career throwing for 158 yards, 88 of which came in the first quarter when the UTSA defense was focused on stopping Carey.

“We were just going off what the defense was giving us,” Denker said Saturday.

Carey’s chances of breaking 2,000 total rushing yards may be bleak, but there’s no denying his talent and the power he brings to Arizona.

“All of our guys run hard,” Rodriguez said. “But Ka’Deem Carey may run hungrier than any running back in college football.”

—Follow Luke Della @LukeDella