TEMPE, Ariz. -- Arizona Cardinals quarterback Carson Palmer was excused from Wednesday's practice by coach Bruce Arians to seek another opinion on his injured right shoulder.
Arians said Palmer regressed while throwing Thursday and Friday during Arizona's bye week. The shoulder swelled around the nerve, putting Palmer's status for Sunday's game in Denver in doubt.
"Hopefully, he'll be back tomorrow and throwing soon," Arians said.
Arians wasn't prepared to rule Palmer out of Sunday's game. The Cardinals head to Denver as one of two undefeated teams left.
Arians called Palmer doubtful for Thursday's practice, but if the 34-year-old returns by Friday, there's a chance he can start this weekend. If Palmer doesn't practice Friday, he won't start but could be available as Arizona's backup, Arians added, meaning Drew Stanton would get his third straight start.
"We need to see two good days or a day-and-a-half of his full-speed delivery and not a soft toss," Arians said. "He's got to be back to full tilt."
Palmer was throwing 30 to 40 yards last week, but after throwing for two days the injury reverted "fairly close" to its initial state, he said. Palmer suffered the injury in Week 1 against San Diego.
The Cardinals are still treating Palmer's injury on a week-to-week basis, but they have the option of putting him on injured reserve/designated to return for just a few more weeks.
"We're not even close to that yet," Arians said.
Arizona has until Week 8 to decide if Palmer would go on IR/designated to return, because at Week 8 or later, he'd miss the rest of the regular season.
Palmer was "very frustrated" with his setback and Arians is frustrated for his quarterback.
"It's just part of the business," Arians said. "I'm frustrated for him because I know how much it means to him, how much he's put into it to get here, and you don't like to have [a team captain] going out for the coin toss in shorts."