TEMPE, Ariz. - A visit to a spine specialist confirmed what already had been diagnosed: Arizona quarterback Carson Palmer has a "dead" nerve in his throwing shoulder.

Palmer visited the specialist on Wednesday, and said Thursday that no structural damage was detected.

"No surgery," he said. "It's not career ending, it's not season ending, nothing like that. So that was all positive. I'm just going to continue to do the rehab I've been doing with our guys and I'm very confident it's going to wake back up."

Palmer said the doctor told him the chances were one in 100,000 of him falling on the shoulder in just the wrong way to put pressure on the nerve and "shut it down."

"I can get tackled thousands of times," he said, "it just happened that my arm was in the wrong position."

Palmer has not officially been ruled out of Sunday's game at Denver, but all signs point to Drew Stanton making his third straight start.

The shoulder felt better a week ago so he did some throwing, activity that irritated the nerve again.

"I threw 20 per cent of what I typically throw as far as velocity is concerned," he said. "I haven't gone out there and just chucked the ball all over the field. That's not what they've told me to do."

It was enough to cause his shoulder to regress.

"One of the things I've learned is that nerves are very finicky and they're very unpredictable," Palmer said. "It's not like a sprained ACL where it's a 2-4 week thing. It's just something where I've got to continue to work and when it's ready, it's ready."

He said this isn't a typical football injury.

"The doctor I saw yesterday sees them a lot in car accidents," Palmer said. "So it's not something that's just kind of run of the mill."

He acknowledged being frustrated but said it's his nature to have a positive attitude.

"I'm taking it one day at a time," Palmer said. "I'm coming in every day. I'm the first in here and the last to leave every day. I'm preparing that when it turns on, I'm ready to go."

Arizona (3-0) enters Sunday's game as a touchdown underdog but as one of two unbeaten teams remaining in the NFL.

Palmer's shoulder was hurt when he landed on it while trying to run for a first down in the Cardinals' 18-17 season-opening win over San Diego. Stanton, who had not taken a snap in a regular-season game in four years, came on to direct Arizona to a road victory over the New York Giants, followed by a home win over San Francisco.

The team had a bye last week, and Palmer was hopeful that time off would allow him to be ready to play.

"I'm just going to stick with the protocol and hope and pray that it wakes back up," he said. "... We've tried everything. They (his doctors and trainers) have done a great job of doing research, calling different doctors all over the place, calling people all over the country, trying to find out if anybody has any information on it."

He has tried "dry needle" treatment, deep-tissue massage and acupuncture.

While he waits for the nerve to respond, Palmer said he's doing what he can to help the team.

"I'm going to do everything I can to help guys around me," he said, "to help Drew obviously, and I'm always on the receivers and skill position guys during practice and in meetings, helping out any way I can. And I'm going to continue to stay positive and be as influential as I can without getting in the way."

___

AP NFL websites: http://www.pro32.ap.org and http://twitter.com/AP_NFL