TEMPE, Ariz. -- Five months ago, when the thought of Josh Rosen standing behind a podium as the Arizona Cardinals' starting quarterback was first imagined, the possibilities of what could come out of his mouth were endless.

He developed, doubled down and reaffirmed his reputation as the quarterback with the big arm, bigger opinions and smart mouth through years of being open and honest about how he felt on a variety of topics, from Donald Trump to the NCAA and everything in between.

But since Rosen was drafted 10th overall -- nine places lower than he thought he should've been picked -- his loquaciousness has calmed. He made his now-famous remarks on draft night about there being "nine mistakes" ahead of him, which he revised the next day to just "three big mistakes," referring to the three quarterbacks.

Since then, however, Rosen, publicly, has been a quiet shell of his college self.

On Wednesday, toward the end of the first news conference as the Cardinals' starter, Rosen was asked why he has been so quiet.

"I'm just busy," he said.

Anyone who was surprised by that answer hasn't paid attention to the 21-year-old rookie.

He has hinted this was how he'd handle his early days in the NFL. At the NFL scouting combine, Rosen said, "there's a time and a place for everything." About everything.

"You might not want to speak against the president in the playoffs or before you have a starting job on a team and actually have a voice," Rosen told ESPN The Magazine in April.

He knew he needed to be seen and not heard. But that's not how it has always been.

When Rosen decided to give up tennis at the age of 13 after a junior career that saw him reach the No. 1 ranking in Southern California and into the top 50 in the country, he told his coach, Steve Whitehead, in a very Rosen way.

"He was, like, 'By the way, Steve, I'm not playing,'" Whitehead said. "It was very casual."

And when Rosen committed to play football at UCLA, he did so with little suspense. He put three hats on the table in front of him, as has become a common tradition among top recruits picking their colleges. The difference, however, was that all three of Rosen's were UCLA hats.

The football world outside the confines of Rosen's high school, St. John Bosco, located outside Los Angeles, saw what kind of mind Rosen had during the summer going into his senior year of high school.

He attended the prestigious Elite 11 camp during the summer going into his senior year of high school. There, he clashed with instructors, including former NFL quarterback Trent Dilfer, who ran the camp.

"He looks what people think a quarterback should look like," Dilfer said, according to 247 Sports. "He's big, he's strong, he makes the very difficult look easy. He's super, super smart, but I think it is almost a curse for him. Josh is a guy who has yet to buy in to what I am preaching. He's still a guy who keeps telling me how they do it at John Bosco."

Rosen's high school coaches weren't surprised. They knew how inquisitive Rosen was and they knew how to handle it. Outsiders, however, didn't and criticized the prep star.

"They took it as him challenging them and it went south from there," said Chad Johnson, Bosco's offensive coordinator. "He'd been allowed to ask questions here, and there they didn't have time to go through the why, why, why."

Rosen's complex, intelligent and advanced mind had made its national debut. It'd soon define him to those who didn't watch him play football.

By becoming the Bruins' starting quarterback at 18 years old, Rosen inherited the role as a face of the university. Unbeknownst to anyone at the time, the next three years would bring plenty of attention, both wanted and unwanted, to Rosen and UCLA.

Six weeks into Rosen's freshman season, his first controversial social media post hit the internet. Two days after UCLA got swamped by Stanford on Oct. 15, Rosen posted an Instagram video of him eating in a hot tub in his dorm room. The same day, a young woman posted a photo of her in the same hot tub with Rosen.

Backlash ensued.

"I accidentally shipped it to my mom's house," Rosen told ESPN The Magazine in April. "My mom thought it was hilarious and drove it up for me. I thought it was hilarious because she did. But I shouldn't have had a woman in there.

"I enjoy making people laugh, but what I find funny and put online, others might misconstrue and find jerkish."

On the field, Rosen was establishing himself as one of the premier quarterbacks in college football, but Rosen's Instagram account drew more attention than his play.

On April 11, 2016, he posted a photo of him golfing at Trump National Golf Club in Rancho Palos Verdes, California, wearing a hat with a message wrapped around it that said: "F--- Trump."

In late May, Rosen again made headlines with another social media post. This time, by sharing his feelings about the $280 million deal UCLA had signed with Under Armour to be the school's athletic apparel company.

"We're still amateurs though. ... Gotta love non-profits #NCAA," Rosen wrote as his caption.

By time he went back to school for his sophomore season, Rosen's opinionated, outgoing personality was as much of a topic as his football prowess.

His first Sports Illustrated cover, published in August 2016, had the subhead: "Big Arm? ✔️ Big Mouth? ✔️"

But Rosen didn't see the problem with being an honest and outspoken college athlete.

In an interview with Bleacher Report he questioned why people doubted he loved football, declaring he wanted to play 15 years in the NFL.

"I don't love the game? Really?" Rosen asked, according to Bleacher Report. "If I didn't love the game, I wouldn't be out here getting my ass kicked."

Rosen also re-entered the student vs. athlete conversation yet again. In a big way.

"Football and school don't go together," Rosen told Bleacher Report. "They just don't. Trying to do both is like trying to do two full-time jobs. There are guys who have no business being in school, but they're here because this is the path to the NFL. There's no other way.

"Then there's the other side that says raise the SAT eligibility requirements. OK, raise the SAT requirement at Alabama and see what kind of team they have. You lose athletes and then the product on the field suffers."

"OK, raise the SAT requirement at Alabama and see what kind of team they have. You lose athletes and then the product on the field suffers." Josh Rosen

Rosen, who was an economics major, said football "really dents my ability to take some classes that I need."

"Human beings don't belong in school with our schedules," Rosen said. "No one in their right mind should have a football player's schedule, and go to school."

Rosen sticks up for what he believes in. He saw the inequities in college athletics and spoke his mind. He saw the flaws in life as a "student athlete" and challenged them.

At the Cactus Bowl media day in December, he said something that reverberated throughout the NFL when he was asked if he felt strongly about teams he'd prefer to play for.

"Kind of," Rosen said. "I think the teams know more than I do in the sense of where I'd best fit. I might be a bit of a unique personality so hopefully they can pick me apart and if a team really feels that I'm their guy, hopefully they'll go and get me. I'd rather be a lower pick at the right team than a higher at the wrong team."

On Christmas Eve, ESPN NFL Insider Adam Schefter reported Rosen preferred to play for the New York Giants, who had the No. 2 pick, than the Cleveland Browns, who picked first, and if Cleveland planned on drafting Rosen, he'd be hesitant to come out early.

Soon after, Rosen declared himself for the 2018 NFL draft and even more microscopes came out.

At the NFL combine in March, he declared himself the best quarterback there, personality and all.

"I'm not going to change who I am," Rosen said. "I still am me."

During a wide-ranging interview with ESPN The Magazine published on April 10, two weeks before the draft, Rosen called himself "pretty arrogant."

"They handed an 18-year-old the keys to a DI FBS-contending university," Rosen said. "I blew up a little bit, said some things I didn't mean, and that follows you. You get one chance to make a first impression. I made the wrong one."

He said he wanted to win six Super Bowls and if New England quarterback Tom Brady won a sixth, then Rosen wanted to win a seventh. He said "you have to be" cocky in football but you have to know how to harness it. He said being labeled a "jerk" is a "blessing in disguise." He said his Instagram post about Under Armour was "pretty s----y" and had second thoughts about the dorm room hot tub.

Two weeks later, Rosen sat in the green room for the first round of the NFL draft at AT&T Stadium, watching three quarterbacks chosen in the first seven picks. He wasn't happy. Then the Cardinals moved up five spots to take him at No. 10.

It was bittersweet and he quickly told reporters at the draft that "there were nine mistakes ahead" of him.

"I thought I should have been picked at one, two or three," Rosen said. "I dropped, and I was pissed. I was really, really angry. I wasn't really showing it, because I was trying to keep calm, composed and cool. I thought I was going to get picked, and I thought that I was going to have to put on a face and try and fake happiness."

Rosen had a theory for why he fell.

"Maybe if I had shut up these last three years I could have been picked higher, but I don't want that," Rosen said. "I want to be me and the Arizona Cardinals know what they are getting. They are not getting a kid that is going to say stupid things and piss people off unnecessarily. They are going to get a kid that everyone knows who they are getting every single day I walk into the building."

The day after the draft, Rosen walked back his emotional statement .

"I was a little emotional last night, Rosen said. "I would actually say that I'm not as angry that there were nine guys ahead of me, just the three quarterbacks. That's kind of what gets to me. So, there were three big mistakes ahead of me, but honestly, it's a blessing in disguise."

Rosen has been quieter and more reserved in the NFL. During the offseason and the start of the regular season, he kept his head down, understanding his role as a rookie backup.

He began his NFL career on the bench, the first time since his freshman year of high school that he was healthy and not starting. But Arizona started the year 0-2 and starter Sam Bradford struggled.

The Josh Rosen era began with 4 minutes, 31 seconds left in the fourth quarter in Week 3 against the Chicago Bears. A day later, Wilks said Rosen would be the team's starter going forward.

"I prepared every single week up to this point as if I was the starter because anything can happen, and something has happened," Rosen said Wednesday. "It doesn't change my preparation. I'm always balls to the wall all the time."

Rosen's first career start came Sunday against the Seattle Seahawks.

Even though the Cardinals lost, Rosen impressed. He threw for 180 yards and a touchdown, but his poise drew rave reviews.

Suddenly, a confident, yet reserved Rosen emerged. Whether that's here to stay, only the rest of Rosen's career can answer that.

"... hopefully," Rosen said, "I'll be in the NFL for a while."