And that means they're not taking any chances this offseason.
The 37-year-old Palmer "probably" won't throw until the final week of Arizona's offseason practices, which will be the June 6-8 minicamp, coach Bruce Arians said last week.
"He's just doing everything mentally," Arians said. "He tosses some soft ones around in the blitz drills but he doesn't need to be out there right now. We got four arms for both fields because we're always going to have our dual practices."
Arians told ESPN he felt Palmer "overworked" last summer, which led to the Cardinals needing to build in time for him to rest. By early November, Arians gave Palmer every Wednesday off. That will continue this season, Arians hinted at the NFL's annual meetings in March.
Arians said Palmer has lost a few pounds and is "healthier, stronger, looks better than he's ever done."
Overall, Palmer "looks great," Arians said.
The extra day of rest helped Palmer down the stretch last season. Arians said Palmer played "great" in November and December after the team was able to get his arm under control. He threw for 2,165 yards, 16 touchdowns and eight interceptions with a completion rate of 59.4 from November onward.
"Carson's an overworker," Arians said. "We've learned now how to deal with it."