Bruce Arians says Carson Palmer dealt with a fatigued throwing arm last season.
Palmer had an up-and-down 2016 campaign.
"He's one of the hardest working dudes I've ever been around, so we have to pull the reins back on him," Arians told The Rich Eisen Show. "Last year, he came in to September, he had already wore his arm out by overthrowing all summer. We found a nice regimen, [and by] November and December he was playing as good as he's ever played."