PHOENIX (AP) -- With three tailbacks combining to rush for 54 yards, No. 15 Arizona State appeared to struggle to run the ball against overmatched Northern Arizona in its season opener.

Coach Dennis Erickson saw it a different way.

"You're talking about one game where we played a team with an eight-man front," Erickson said Monday at his weekly campus news conference. "To me, it's pretty hard to judge anything in our running game. Obviously that was a conversation because it was one of the few things we didn't do as well as people thought."

Either way, the Sun Devils (1-0) may need a more balanced attack when they face Stanford (1-0) in the Pac-10 opener for both teams on Saturday night in Tempe.

The Sun Devils missed senior tailback Keegan Herring, who has a hamstring injury. He may miss this week too.

"Do we have to become better with running the football? Without a doubt," Erickson said. "We have to do it a little bit better than we did the other night. But again, if we were halfway through the season and we weren't running the ball very well I would have some concerns. But because of what NAU did to us we didn't run it that much."

Against Stanford, the Sun Devils may have to rely on quarterback Rudy Carpenter, who had a big first game. He completed 22-of-28 passes for 388 yards and a touchdown, and he tied a school record with 13 straight completions.

Carpenter, a senior, said he's becoming more comfortable after one season in Erickson's offense.

"I wasn't as comfortable as I would have liked to have been last year, but this year we put in a lot of work during the offseason and spring, so I have a better grasp of the offense which allows me to make decisions faster," Carpenter said. "So it does feel like the game has slowed down for me and I can just pick what I want to do. Hopefully, it keeps working out that way."

Stanford will provide a much tougher test for the Sun Devils, who are in the midst of a four-game homestand to open the season. The Cardinal opened with a victory over Oregon State in Palo Alto, and they're much improved under second-year coach Jim Harbaugh, who inherited a 1-11 team.

"The attitude from the time Jim has taken over has completely changed," Erickson said. "They are a really good football team. We're going to have to be very prepared. It's our Pac-10 home opener. Those are the ones that count the most."

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