TEMPE, Ariz. — Arizona State coach Dennis Erickson said he wants to see how quarterback Rudy Carpenter's sprained left ankle responds before deciding whether he'll play at No. 8 USC on Saturday.

Carpenter was hurt in the Sun Devils' 24-14 loss at California last weekend. The senior has made 36 straight starts, but that streak could be in jeopardy.

"First of all, we need to get the OK from the doctor, and then see how he moves out there (in practice)," Erickson said at his weekly campus news conference on Monday. "I'm not going to put him on the field unless he has the mobility to be able to move and throw. He has to be pretty close to 100 percent."

If Carpenter can't play, the Sun Devils would turn to junior Danny Sullivan, who has completed 1-of-8 passes for minus-1 yard this season.

Erickson said that Sullivan, who has appeared in all five games, would be ready to play if needed.

"He is very competitive and he knows what we're doing, so if that's the case, he will do a good job," Erickson said.

The Sun Devils (2-3, 1-1 Pac-10) have dropped three straight games after opening the season ranked No. 15 in The Associated Press Top 25.