"Cardinals quarterback Derek Anderson already has something Matt Leinart never fully had: teammates who believe in him.

"I'll tell you what," center Lyle Sendlein said Monday. "He's got a lot of respect from us for taking those hits and staying in there."

One hurdle solved; another awaits. He must prove that he's more than a strong-armed quarterback with accuracy issues.

He didn't do much to dispel the rap Sunday in a 17-13 victory over the St. Louis Rams. He completed 53.7 percent of his passes (22 of 41) which is in line with his career mark of 53 percent.

His completion percentage ranked 23rd in the NFL after Sunday's games. Typical Anderson, many thought, but coach Ken Whisenhunt disagrees.

"I don't buy into that," he said. "I think he missed some throws. . . . but the guy hung in there, and he made a big throw at the end of the game to win it for us. That to me means you have a lot to work with, and I'm excited about that."

After a breakthrough 2007 season, which included a Pro Bowl appearance, Anderson's percentage dropped steadily, from 56.5 percent to 50.2 to 44.5. He didn't have the type of receiving talent his past two seasons in Cleveland that he has here, but it's clear his mechanics took a backseat somewhere along the way.

The Cardinals saw enough in Anderson's past performances to believe they could shape him into a more-efficient quarterback. There was evidence Sunday that they might be right.

Twelve of his 19 incompletions against the Rams came on passes to Larry Fitzgerald. Take Fitzgerald out of the equation, and Anderson was 19 of 26 for 73 percent.

Chemistry and timing is an issue. Fitzgerald lamented about it last week, expressing concern that Anderson practiced primarily with the second team in the off-season and that the wide receiver's sprained knee ligaments slowed his progress.

Fitzgerald clearly was bothered by the injury against the Rams. Botched routes and miscommunications also played a role.

Early-season stuff, according to Whisenhunt. The coach pointed to the 2009 opener, when starting quarterback Kurt Warner posted Anderson-like numbers: 26 of 44 completions (59 percent) for 288 yards and two interceptions."