Cornerback Richard Marshall (right) celebrates an interception with Patrick Peterson in Philadelphia. The play was later overturned on replay.

The Cardinals haven't given up a touchdown pass in three games, the first time since 2005 that has happened.

It's the same time frame the secondary broke out a new slogan: "Protect the paint."

"We don't want anyone scratching up that classic car," cornerback Patrick Peterson said. "That's kind of the mentality right now, protecting the end zone, and we have done a pretty good job the last couple of weeks."

The quarterbacks the Cards have shut out isn't a bad list: Joe Flacco, Sam Bradford, Michael Vick. You can parse the statistic – against the Ravens, for instance, the secondary couldn't stop Anquan Boldin and the passing game allowed Ray Rice to score three short rushing touchdowns – but there is a feeling of correlation between the stat and improvement.

"I feel like we are communicating better in the back end and that has been key," cornerback Richard Marshall said. "Getting together and making sure everything is right. We talk before every play, even in practice, and on the sideline we talk about what just happened. We are starting to play as a unit now."

Peterson is playing better and Marshall has been solid as a swing man, starting at corner and moving to free safety in sub-packages against the pass. The other cornerback, A.J. Jefferson, nabbed his first career interception last week.

The pass rush has also improved with the play of young linebackers Sam Acho and O'Brien Schofield, and the criticisms of the secondary are quieted a bit.

"It's (been) hard, but we have to understand," Marshall said. "We had young guys, and they are starting to grow up. We had guys up and down as far as knowing it and not knowing it."

Defensive coordinator Ray Horton said he was hopeful the secondary has reached a new level of performance.

"It's getting comfortable of what is going on and what you are trying to take away," Horton said. "The big thing we have always stressed is, this league, every once in a while they are going to score some points and make some plays. What we try to stress is, give them the small stuff and not give up the big stuff and that wins games."

SKELTON AT BEGINNING, END

Through two starts, John Skelton's numbers are stark. In the first three quarters, he is 24-for-45 for 299 yards, one touchdown, one interception and a passer rating of 72.4.

In the fourth quarter, he is 17-of-30 for 238 yards, three touchdowns, one interception and a passer rating of 101.8.

Why that is, Skelton himself can't answer.

"I don't know," he said. "Not having many nerves, I guess, and just being able to execute. You just have to focus on one play at a time. You have to have that sense of urgency. We turn it up a notch in the fourth quarter."

BEANIE VERSUS THE NINERS' WALL

While running back Beanie Wells is fighting through knee issues yet continuing to be the Cards' workhorse back, he now will face a difficult task in the 49ers' top-ranked run defense. San Francisco is allowing just 73.2 rushing yards a game and has yet to allow a rushing touchdown. As the Sacramento Bee's Matt Barrows broke down, no running back has a rush of more than 16 yards against the Niners all season.

"It's all about what I do and how I prepare," Wells said. "It's not so much about them."

Wells acknowledged the recent plane trips have hampered him, but "I think as the week goes on, it calms down." Coach Ken Whisenhunt said Wells will play unless something unforeseen crops up before kickoff.

KOLB OFFICIALLY QUESTIONABLE

Quarterback Kevin Kolb was limited against in practice and officially is questionable for the game, although all signs point to Skelton making his third straight start in San Francisco.

Kolb was one of nine players listed as questionable: Wells, cornerback Michael Adams (hamstring), tackle Jeremy Bridges (back), tackle Brandon Keith (knee), tight end Todd Heap (hamstring), tight end Rob Housler (groin), linebacker Paris Lenon (groin) and fullback Anthony Sherman (ankle).

Linebacker Stewart Bradley (ribs) practiced fully Friday and is probable, as is running back LaRod Stephens-Howling (shoulder). Safety Kerry Rhodes (foot) and linebacker Joey Porter (knee) remain out.