PEORIA, Ariz. -- George Kirby spent the baseball portion of his offseason in solitude.

When the Mariners’ All-Star pitcher began his throwing program, he did so exclusively hurling at a nine-square pitchers’ net while training at an indoor facility near his childhood home in Rye, N.Y., just as he has since joining the organization in 2019.

No catcher, no talking, no nonsense. The only sounds were the dubstep tunes echoing in his noise-canceling headphones.

“I like the crazy stuff,” Kirby said.

There were only a few exceptions to Kirby’s seclusion, including one that wasn’t exactly timely. While in the Tampa area for the holidays, down the street from where Mariners pitching coach Pete Woodworth makes his offseason home, Kirby had an itch.

“Hey, can you throw today?” Kirby texted Woodworth.

“George, I’m a little busy at the moment,” Woodworth responded in between opening gifts with his two youngsters, laughing about it two months later.

These moments represent a microcosm of the uber-competitive Kirby, who is coming off a season in which he finished eighth in the American League Cy Young Award voting and pitched in his first All-Star Game -- coincidentally at T-Mobile Park.

The righty was MLB’s 11th-most valuable pitcher by FanGraphs’ wins above replacement (4.4) in 2023 while compiling a 3.35 ERA, 120 ERA+ (league average is 100) and a 9.05 strikeout-to-walk ratio, the eighth-best in AL/NL history. Some in the industry forecast that it’s not a matter of if he’ll win a Cy Young, but when.

Yet, Kirby also navigated the balance of his fiery intensity, which at times lingered off the mound -- particularly following starts that were, by his estimation, subpar.

“I want to go seven innings, I want to strike out 10 guys or whatever it is,” Kirby said. “So I'm not pleased if I don't have the line that I set up in my head. So I've just got to be easier on myself. It's a long game.”

Does he feel better about processing those moments?

“Yeah, I think so,” Kirby said. “I think it's a matter of just being able to debrief and watch yourself give up seven runs or something. I would kind of just ... let it linger. I think a good step for me this year is kind of just diving into -- not like video necessarily, but kind of understanding who I'm facing more, get a better understanding of how to attack these guys.”

Kirby’s competitive nature is what got him here, and the Mariners don’t want to change that. But there’s recognition that harnessing it could better optimize it.

“When it's your day to pitch, go be as intense and just be an animal,” Mariners manager Scott Servais said. “Be ready to go after them and compete, and George is that. I think there are other times, it's hard to stay at that level every day, otherwise, it'll just wear you out. So when it's not your day to pitch, maybe it's the day after you pitched or on your side day, whatever, then you can kind of turn the volume down a little bit. And I think he's learning that.”

On the mound, Kirby enters spring without stringent workload limitations that he faced the past two years. The Mariners will monitor him like just about every arm other than Luis Castillo, but on the heels of throwing 190 2/3 innings last season (tied with Logan Gilbert for 14th most in MLB), he’s growing into a workhorse.

The book is out on Kirby being MLB’s most aggressive strike-thrower, but Kirby believes he’s prepared to adjust back. He added a two-seam fastball mid-season in 2022, the splitter in '23 that became a true weapon in the season’s final months, and of course, the knuckleball that he unveiled in Game 162 last season -- when he baffled eventual World Series MVP Corey Seager.

Kirby has already thrown it during bullpen sessions and teased that it may go beyond that.

“It needs some work still,” Kirby said. “They weren’t great. It’s going to be a hard pitch to locate, that’s for sure, to kind of throw from my normal windup. But I’m going to try to mix it in once a game or something.”

Servais jokes otherwise.

“We’re going to focus on what George is really good at, and I think he knows that,” Servais said.

The knuckler may be TBD, but Kirby nonetheless appears poised for another big year.