Josh Rosen's throwing mechanics are a thing of beauty. The Cardinals' rookie quarterback has a textbook start-to-finish process that can be a guide for other quarterbacks working on the fundamentals.

But there are times when he abandons it completely.

Rosen has shown a willingness to improvise with arm angles in different situations during training camp. Most notably, he will fire sidearm passes when offensive coordinator Mike McCoy calls a wide receiver screen.

While the arm action may not be as fundamentally sound as an over-the-top throw, Rosen's goal is to get the ball out quickly to the receiver while avoiding the paws of a defensive end, and he believes slinging it sidearm is the best approach.

"I think as a quarterback it's a very valuable trait," Rosen said. "It's not about just how hard or far you can throw it. It's being able to change your arm slot and delivery."

Rosen has developed a friendship with Aaron Rodgers over the past few months, and singles out the Packers quarterback as the king of arm slot improvisation. The concern about sidearm passes is a lack of accuracy due to the unique process, but Rosen said no coach has ever broached the idea of taking it out of his repertoire.

He plans to rely on it in situations when a standard pass is suboptimal.

"Mid-throw you will see windows as guys' hands are up," Rosen said, "and your ability to change your arm slot and throw sidearm to fit a quick screen in there, or just contort your body to get halfback screens in there, I think that's probably one of the more valuable traits from a throwing perspective."