Tempe, Ariz. ? Arizona coach Dennis Green calls the Cardinals’ most recent offensive performance “ludicrous.”

According to the dictionary, that means “so absurd, ridiculous or exaggerated as to cause or merit laughter.”

Green wasn’t chuckling Monday as he talked about replacing mistake-prone Kurt Warner with rookie Matt Leinart, a decision he announced Sunday after a 32-10 loss to the Falcons in Atlanta.

“He’s a guy that had an incredible career in college,” Green said. “I think he’s worked hard to try to learn and understand the pro game, and I think he’s ready to play.”

The Kansas City Chiefs will present a particularly tough challenge to Leinart’s ability to read NFL defenses.

“They use a lot of different fronts,” Green said. “They’ve got an outstanding defensive staff, and they like to give you a lot of confusion, so he’s got to make sure he doesn’t always bite on what he thinks he sees.”

While Leinart waited in the wings with apparent patience, there is no doubt he was anxious to get on the field.

“I’m not an arrogant or cocky person, but I have a lot of confidence,” Leinart said. “I feel I can play.”