Carson Palmer wasn't at practice Tuesday, but that was planned all along. The quarterback was going to sit out to rest his legs, and backup quarterback Drew Stanton was scheduled to sit out Wednesday.

That it was the plan was important, since Palmer is coming off an ACL tear and Monday, in his first day in the pocket of padded 11-on-11, Palmer had his legs taken out -- making everyone in University of Phoenix Stadium gasp for a moment.

Palmer immediately jumped up in the middle of the two-minute drill for the next play, but that didn't make it any easier for coach Bruce Arians or blitzing safety Tyrann Mathieu, who knocked running back Kerwynn Williams into Palmer.

"My heart was in my behind," Mathieu said. "It was tough, man. We are feeling pretty good as a team right now so I certainly didn't want to be responsible for No. 3 (Palmer)."

It was easy to crack jokes Tuesday given that Palmer was fine. It was noted to Arians Palmer didn't seem bothered by the play. "It scared the (expletive) outta Ty though," Arians deadpanned.

Arians said the play happened because Mathieu stopped on his blitz, leading running back Kerwynn Williams to let up on his pass block – only to have Mathieu then follow through on the collision. Williams fell back into Palmer.

"Half the guys who blitz stop, some don't," Arians said. "That's one of the things we have to correct. Come full speed or don't come full speed, but you don't stop and then hit a guy who has already stopped."

Mathieu admitted he thought he was going to get kicked out of practice. Arians, surprisingly, did not yell at him.

"Which was weird because usually he gets pretty pissed off at those types of things," Mathieu said with a smile.

Mathieu said Palmer wasn't mad, telling Mathieu it was just football. Still, Mathieu said he wants to be more careful.

"There is a line you don't want to cross, and obviously I crossed it," Mathieu said.

ARIANS PHILOSOPHY ON STRETCHING ISN'T CHANGING

Arians acknowledged he has gotten angry at the timing of some of the hamstring injuries his team has suffered,

especially with young players for whom he wants to get a lot of practice.

But as for the idea of stretching as a team – something Arians has never done – he shrugged it off once again, noting that this day and age of the players and personal training, they can prepare their bodies for practice.

"You can't stretch a cold muscle," Arians said. "They're here riding bicycles, rubber bands, trainers, they know their body to start practice. They are out there running, they've worked out and warmed up. We're not going to waste 25 minutes on the practice field to stretch somebody that's scientifically figured out it ain't worth a (expletive). Jumping jacks and touching your toes, that ain't getting (expletive) done."

NO CHANGES ON THE INJURY FRONT

Speaking of injuries, Arians said there are no changes. Running backs Andre Ellington and David Johnson and linebackers Shaq Riddick and Sean Weatherspoon will all sit out with hamstring issues. Linebacker Darryl Sharpton (hip flexor) is also sitting. Tight ends Jermaine Gresham and Troy Niklas are also mostly spectators as they come off PUP and NFI, respectively.

With Palmer sitting out as a planned rest Tuesday, Logan Thomas will be the No. 2 quarterback today. Arians didn't commit to Thomas being No. 2 Wednesday when Stanton gets his day of rest.

During Tuesday's practice, first-round draft pick D.J. Humphries left early with an apparent knee injury. Running back Marion Grice, guard Earl Watford and tackle Rob Crisp also had their days cut short by injuries.

CORNERBACK SIGNED

The Cardinals signed cornerback Jonte Green Tuesday. Green, who attended the Cards' rookie minicamp, has played in 24 NFL games with the Lions and Bills. The Cards cut cornerback Damond Green.