It has been "years," Rosen said, since he spent his January away from football or out of a weight room. During his three seasons at UCLA, Rosen was under a "pretty strict" strength and conditioning schedule that had him in the weight room at 6 a.m. from Monday through Friday, he said. His only off times were winter break, spring break and finals week.
And, now, with the Cardinals not in the playoffs, Rosen finally has an opportunity to relax, recover and reflect after a turbulent rookie season.
"It's going to be nice to get a breath of fresh air," Rosen said.
He won't have to be back in Arizona for any football-related activities until early April, when the Cardinals open their strength-and-conditioning program. Rosen plans to get away this month. He'll head to Australia to watch the Australian Open.
It'll give him time to put a rookie season that fell far below expectations behind him.
The Cardinals (3-13) struggled, winning fewer than four games for just the second time since 1959, and Rosen did as well. The 10th overall pick in the 2018 draft threw 14 interceptions and 11 touchdown passes. He completed just 55.2 of his passes for 2,278 yards. He didn't throw for 300 yards once and was sacked 45 times while finishing the year with a Total QBR of 26.1. Overall, Rosen finished at or near the bottom of the league in 13 categories, and he had four of the 10 worst games of Total QBR all season.
"It was a very difficult learning experience," Rosen said. "But it was a learning experience."
And it's why the Cardinals hired Kliff Kingsbury as their new coach this week. Kingsbury is already impressed with what he's seen.
"Josh Rosen is incredibly talented, one of the most talented throwers you'll see," Kingsbury said. "A young player, obviously, that I'm excited to work with and develop. But as a pure thrower, it's hard to find a guy that throws it better."
Rosen was drafted to sit behind and learn from veteran quarterback Sam Bradford this season -- which he did for almost three games. But Rosen was forced into action at the end of a Week 3 loss to the Chicago Bears and didn't look back, replacing Bradford as the starter a week later.
"I understand the positives and the pitfalls. I can say I would have liked to sit, but probably by Week 6, 7 or 8, I would've been like, 'I'm over this,'" Rosen said. "Hindsight's 20-20, so I don't know how I would've reacted."
By late in the season, Rosen said he was "definitely a lot more comfortable" behind center than he was in Week 3. That comfort came incrementally, thanks in part to former offensive coordinator Byron Leftwich, who Rosen thought was "slowly putting more and more on my plate without even telling me."
Rosen's development in 2018 came down to one thing: experience.
"I think mistakes are valuable," Rosen said. "You want to minimize them, but more importantly, you don't want to make them twice. I've made plenty of them this year, and hopefully I'm, for the most part, not making the same mistakes twice, just finding new ones to make."
Rosen will be better prepared for the grind of the NFL calendar next year as well. He said he hit the rookie wall with a mix of mental and physical fatigue, something he hadn't experienced before. In college, Rosen said, he got breaks from football, with such breaks coming when he was in class, hanging out with friends or engaging in other social activities. Those breaks weren't there this season.
"It's just football all the way through, all day, every day," Rosen said. "Your brain's getting choked out and you start to tap a little bit. Maybe like that Wednesday or Thursday, and you've got to convince yourself to refocus and keep pushing on."
When he finally hit that wall, the fatigue came on fast and furious.
"I slammed right into it in Atlanta," Rosen said.
That was Week 15. Rosen gradually navigated through it.
"It's like breaking up with a girlfriend," Rosen said.
He'll adjust his routine. Without having to prepare for the combine, his pro day and the draft, Rosen feels the time away will be good for him.
Every step of his rookie season was another lesson. Every setback was a chance to rebound. Each experience taught him something new.
But will all of that collectively make him a better quarterback in 2019?
"Yes," he said. "That's a question with one answer."