Posted by ESPN.com's Ted Miller

TEMPE, Ariz. -- Arizona State quarterback Rudy Carpenter limped into his weekly news conference wearing a boot on his sprained left ankle, not looking like a player who will make his 37th consecutive start Saturday at USC.

He said the ankle feels a little better than it did when he walked out of the postgame locker room after the Sun Devils lost, 24-14, at California, but that he's uncertain whether he'll be able to play.

Carpenter, a quarterback known for his toughness, isn't easy to write off. He got sacked 55 times last year and took numerous other hits and still managed to show up for the first snap every Saturday.

"As long as I can walk," he said, "then I can play."

The Sun Devils need him to play. His backup, junior Danny Sullivan, has never made a start (for obvious reasons), and the running game, now ranked 113th in the nation (85.4 yards per game), has been abysmal.

But this might not be an injury that Carpenter can just play around.

"I'm not going to put him out there on the field unless he has the mobility to move and throw -- he's got to be pretty close to 100 percent," coach Dennis Erickson said.

Erickson termed Carpenter day-to-day. If the quarterback can practice by Wednesday, then he'll likely start.

If not, it's Sullivan, who's big -- 6-foot-5, 238 pounds -- and owns a good arm. Erickson said Sullivan has improved his footwork and knows the offense well.

"He studies as much as any backup quarterback I've been around," Erickson said. "He's going to know what's going on."

Of course, it's different starting than just seeing mop-up duty. And it's different starting on the road.

And it's really different starting on the road against USC.

That's why every effort will be made to get Carpenter ready. It's fair to say that no other Pac-10 player is as important to his team as Carpenter is to the Sun Devils.

"If he plays, it's because he's tough," Erickson said.