" Arizona Cardinals coach Ken Whisenhunt's decision to switch starting quarterbacks for Saturday night's game against the Chicago Bears is designed to ignite a starting offensive unit desperately in need of an accelerant.

Maybe starting Derek Anderson will provide the spark. Or maybe the demotion puts a flame to Matt Leinart's pilot light, which critics believe tends to flicker.

Leinart certainly sounded motivated Friday morning in his first public comments since learning of the demotion a day earlier.

"I'm frustrated and disappointed," said Leinart, who is on the verge of losing the started job twice in four seasons under Whisenhunt. "I've been efficient. I've been accurate. I haven't turned the ball over. I don't know how we judge performance when you take 13 pass attempts to the other guy's 40."

Leinart started the previous two games but has played six series to Anderson's 10 and thrown 28 fewer passes.

Leinart has completed 10 of 13 passes this preseason, but most of those have been short completions. Neither quarterback has benefited from consistent pass protection or a productive running game.

"I'm going to keep grinding and keep fighting," Leinart said. "Ultimately, I have to let my play do the talking. I'm frustrated and disappointed. I'm not really sure what's being asked of me.""