Rookie safety Tyrann Mathieu asks veteran Rashad Johnson a question while Johnson ties his shoe during positional drills at Tuesday's OTA.

For all the noise his story has created, Tyrann Mathieu is a quiet guy.

So in his transition to free safety for the Cardinals, with all its expected bumps and hurdles in changing positions, brings with it an extra challenge for the team's third-round pick when having to call signals for the defense on the field.

"I'm not really a loud guy," Mathieu said after Tuesday's OTA. "So when I have to yell across the field, that's the toughest thing to do. (The coaches) have really been on me as far as speaking up and really emphasizing the calls.

"It takes time and it takes practice," Mathieu added with a chuckle. "This week, I'm definitely louder than I was last week."

That notion drew a nod from veteran free safety Rashad Johnson, who has become Mathieu's transitional tutor. "All last week, I don't think I heard him say anything," Johnson said. "Just saw him in meetings and hanging out. But he's coming around."

So much time has been spent considering the personal aspect of Mathieu’s move into the NFL, but now the focus moves on to the field.

Mathieu hasn't played football since the end of the 2011 season and admitted he needs to get used to football terminology once again.

He did play safety in college at LSU, but only briefly. Teammate Eric Reid – a first-round pick of the 49ers this April – got hurt, and Mathieu "had to step up." Mostly, he played cornerback, and besides, playing safety in the NFL is completely different, he said.

Needing to make checks on defense and vocalizing such things, "I have to step out of my personality and become this loud person," Mathieu said. "It's been fun though."

Mathieu has gotten a little work at cornerback, but mostly, it's been safety and nickel. That's where he'll be playing, and at this point, getting him reps in those spots are the smartest move.

Coach Bruce Arians isn't concerned about the reps Mathieu or any of the rookies are receiving. The rookies have a second on-field session each afternoon after the regular OTA, and that's in addition to the secondary field in use during the regular OTA so the young players are getting work in the system and not just watching the veterans.

"Our rookies probably have gotten more reps already in OTAs than the rest of the rookies in the National Football League put together," Arians said. "(Tyrann) is a guy you only have to tell once and he's got it."

It hasn't hurt that Johnson (and fellow veteran safety Yeremiah Bell) have helped out.

"Rashad has been a key," Mathieu said. "He's the safety in front of me right now and he pretty much has everything down pat. I'm pretty much always picking at him, picking his brain, trying to see how he sees things on the field."

Playing on the outside, playing closer to the line of scrimmage, all those things have changed for Mathieu, Johnson said. Decision-making trumps athleticism. That is something Mathieu must learn.

"You make the checks, you're the quarterback, and a lot of guys are depending on you," Johnson said. "As skilled of an athlete as he is, he'll come around once we sit down and have more time together. He's asking all the right questions, and that's a good thing. It lets you know he wants to learn it."

The process, Mathieu is hoping, will take just the summer, and that he will be steady by the time the Cardinals open training camp. Safety might not have been his first choice, but he smiles thinking about the opportunity.

"It feels so good to be talking about football," Mathieu said. "To make checks (on defense) and not make checks about other things in life."

EXTRA POINT: The Cardinals released WR Javone Lawson waived-injured Tuesday after he tore his Achilles last week. They signed rookie free agent WR Charles Hawkins from Southern to take his place on the roster.