Arizona coach Ken Whisenhunt liked what he saw from Matt Leinart in the Cardinals' preseason opener in Pittsburgh.

Whisenhunt has turned up the pressure on Leinart in training camp by saying Brian St. Pierre has a chance to be the No. 2 quarterback behind Kurt Warner.

Leinart says he's taken it all in stride, and his performance in Thursday night's 20-10 loss impressed the coach.

"He really made a couple of big-time throws," Whisenhunt said at a news conference at the team's practice facility on Friday. "That was nice to see, especially on the perimeter where he's thrown them over guys, fitting them in a window. He was very comfortable in the pocket, very comfortable in the huddle."

Whisenhunt said he was "pleased to see all those things that Matt has been showing us in practice carry over to the game field."

Meanwhile, wide receiver Steve Breaston was to undergo a precautionary MRI because of soreness and stiffness in his knee.

Whisenhunt said he was hopeful that rookie running back Beanie Wells, who sprained an ankle in his first practice, will be able to play in the Cardinals' next preseason game Saturday night against San Diego.

The Cardinals resume workouts in Flagstaff on Sunday, then wrap up training camp on Thursday and return to the triple-digit heat of Tempe.

Whisenhunt downplayed the struggles of St. Pierre against the Steelers.

"I don't think Brian got a lot of help," the coach said. "There were a couple of dropped balls."

He said St. Pierre has played well in camp and will get an earlier chance to play against the Chargers.

The coach also had praise for second-year defensive end Calais Campbell, who has replaced Antonio Smith.

"His challenge is going to be to make that a consistent thing week in and week out," Whisenhunt said. "He's passed the first test, he's taken it from the practice field to the game field. Now the test of whether he can become a really good player is to do it on a weekly basis."