"We're 1-3, man," Mathieu said. "It's not really time for me to sit back and play it slow. I feel good. I feel great. I look forward to wherever Coach puts me at, but if I've got anything to say about it, I'll be back in my normal spot."

The move could be necessitated by the groin injury safety Tyvon Branch suffered in Sunday's loss to the Rams. Mathieu filled his nickel cornerback role the rest of the game, but even if Branch plays against the 49ers, Mathieu is ready to be more involved in the action.

He only had two tackles against Los Angeles, and outside of a forced fumble in Week 3 against the Bills, has been light on the impact plays everyone has come to expect.

"My expectations are extremely high for myself," Mathieu said. "I'll never feel sorry for myself, so I think it's time for me to get back to what I'm doing. I feel comfortable out there. It's time for me to start making plays."

Earlier this season, coach Bruce Arians said he would put Mathieu back into his customary defensive role once the fourth-year defensive back came to him and said he was ready.

Asked if he had told Arians yet, Mathieu smiled.

"I just did," he said.

PASS RUSH TURNS UP THE HEAT

The Cardinals' biggest defensive issue last season was their pass rush, but it performed well against the Rams. Outside linebacker Chandler Jones graded out as the fourth-best player in all of the NFL on Sunday by Pro Football Focus after he accumulated four tackles, a sack, a forced fumble and a fumble recovery.

He has four sacks on the season, as does outside linebacker Markus Golden. Jones, Golden, defensive tackle Calais Campbell and nose tackle Corey Peters graded out as the team's best four defensive players against the Rams by Pro Football Focus.

"We got after it," Golden said. "Our coach said we did good. We watched the film and we did pretty good, but of course we can always do better."

CHRIS JOHNSON MISSES PRACTICE