George Kirby hates walks so much, it just might fuel him to make history.

The Mariners right-hander has 75 strikeouts and only six walks in 87 2/3 innings entering his 15th start of the season Sunday against the Orioles. That's 12 1/2 strikeouts for every free pass, the best in the Majors by a mile -- Kirby's nearly doubling up the next-closest qualified starter, Joe Ryan, who's at 6.67. Kirby hasn't walked a batter in four games. He hasn't walked more than one in a game all season.

"I'm, like, just so obsessed with throwing strikes," Kirby said. "I hate walking people."

So ... he doesn't. Kirby doesn't just have crazy command for a 25-year-old second-year pitcher -- he's on a record pace. Kirby currently has the best single-season strikeout-to-walk ratio of all time for a qualified pitcher.

Highest single-season K:BB ratio, AL/NL history
George Kirby, 2023 -- 12.50
Phil Hughes, 2014 -- 11.63
Bret Saberhagen, 1994 -- 11.00
Cliff Lee, 2010 -- 10.28
Jim Whitney, 1884 -- 10.00

"Walks are just -- I don't know, my whole career, I've just hated them," Kirby said. "I believe in no free bases. I just really stress that: living in the zone and trying to beat guys in the zone."

He's a perfect emblem for the Mariners' "Dominate the Zone" motto, a pitcher who arrived in Seattle hating walks more than anything in the world, and who's blossomed there because of how well he suits the framework that preceded him.

"That's what we do. We find guys that fit our mold," said Mariners pitching coach Pete Woodworth. "George never really walked anybody. 'DTZ' has always been part of George's DNA. Once he got here and saw how important it was, he doubled down on it. And it helped him take off even more."

Kirby gives the Mariners the best of both worlds for their pitching philosophy: the command to fill up the zone and the stuff to dominate it. He's not just a pitch-to-contact strike-thrower like Marco Gonzales. He's not a pure strikeout artist like Robbie Ray.

He's a mix of both, and that lets him roll through opposing lineups with metronomic efficiency and pitch deep into games.

"I was doing it beforehand, too, so I thought it was a pretty perfect situation for me coming here," Kirby said.

And to be clear, it is command, not just basic control, that's driving Kirby to these strikeout-to-walk numbers and a potential All-Star season, as he has a 3.29 ERA and ranks sixth among AL starters with 2.2 Wins Above Replacement.

Kirby doesn't just groove the ball into the zone to collect strikes. He attacks hitters with an array of power fastballs and sharp breaking pitches in a way that they have to swing if they want to score, but it's not easy to make solid contact even if they do hack.

"I think more than anybody that we have, he is command," Woodworth said. "It's not bulk strikes, it's not setting up down the middle, it's not 'All right, I'm just gonna throw a strike here to get into a good count.' He has precise targets that he's going to."

Kirby is a strike-thrower at heart. You can't possibly suppress walks like him if you aren't. He pounds the zone at the highest rate of any regular starter. But he uses his strike-throwing to put the pressure on.

"I just believe that hitting's hard, so you might as well throw it in the zone," Kirby said.

Highest in-zone rate, 2023
Min. 1,000 total pitches

1. George Kirby: 58.1%
2. Mitch Keller: 56.3%
3. Joe Ryan: 54.8%
4. Ryne Nelson: 53.9%
5. Spencer Strider: 53.7%

But, like Woodward said, Kirby isn't just getting "bulk strikes" by throwing the ball anywhere in the zone. He hits his spots with precision. No one throws more strikes on the edges -- which Statcast defines as within one baseball's width of the strike zone borders -- than Kirby.

Highest % of pitches in-zone and on the edges, 2023 
Min. 1,000 total pitches 

1. George Kirby: 26.4%
2. Spencer Strider: 25.9%
3. (tie) Michael Wacha / Matthew Boyd: 25.5% 
4. (tie) Joe Ryan / Kyle Freeland: 25.4%

Kirby's approach to attacking hitters is refreshingly straightforward. Pound the zone with every pitch. But those pitches coming into the zone aren't meatballs. They're two different upper-90s fastballs and a pair of breaking balls with plus movement.

Kirby throws a 96 mph four-seamer and a running two-seamer at similar velocity but with 16 inches of horizontal break. He pairs those with a slider that gets five inches more drop and eight inches more break than an average slider, and a curveball that drops four inches more than an average curve.

But here's what's really interesting. The way Kirby uses his fastballs and breaking balls to get hitters out is flip-flopped from a lot of other dominant pitchers.

Almost all of Kirby's swing-and-miss -- and strikeout totals -- come from his fastball. Only a small portion comes from his slider and curve.

"He's done a really good job of using the breaking balls to their full purpose and potential," Woodworth said. "They may not be wicked two-strike wipeout pitches, but he uses them to get into good counts to then leverage his fastball. He's using them more to win counts, to get weak contact early in counts, to get back into counts. And then putting guys away with the pitches that they swing and miss at, which is more the fastballs."

Kirby's 2023 K's and whiffs by pitch type
4-seamer: 40 K's, 27% whiff rate
Sinker: 20 K's, 18% whiff rate
Slider: 6 K's, 15% whiff rate
Curveball: 9 K's, 14% whiff rate

You'd think Kirby's breaking stuff with its strong movement metrics would be swing-and-miss pitches, especially if he used them to induce chases outside the zone. But that's not who he is. Kirby even pounds the zone with his slider and curveball. He can't help himself.

"There [are] times [when] I would benefit from really expanding the zone," Kirby said. "Sometimes, it's kind of hard for me to do that."

But he wouldn't be George Kirby if he wasn't hammering the strike zone with everything he has in his arsenal. The Mariners embrace that.

"I love what George does," Woodworth said. "That's why he's good. That's why he's going to be good for a really long time."

Over 60% of Kirby's breaking pitches this season have been in the strike zone -- 58% of his sliders and 62% of his curves. No one throws their breaking stuff in the zone more often than him.

Yes, that might limit Kirby's breaking ball swing-and-miss numbers. But because they're such quality pitches, even if they don't miss bats, they miss barrels. Then Kirby dials up his heaters to miss the bats.

So those flip-flopped K totals are really just another product of the way he attacks the zone. A product of who he is at his core.

"You put him in the bullpen and you say, 'All right, your four-seam/slider,' the slider will become a huge weapon," Woodworth said. "As a starter, and with his mentality of filling up the zone, he always kind of does default to that: 'All right, I'm throwing this for a strike,' instead of, 'I'm going to miss your bat.' No, it's: 'I'm gonna throw a strike, and you're gonna be out. I'm gonna make you swing at it.'"

Highest % of pitches thrown ahead in the count, 2023
Min. 1,000 total pitches

1. Joe Ryan: 39.4%
2. Spencer Strider: 37.5%
3. Pablo López: 37.1%
4. George Kirby: 34.8%
5. (tie) Mitch Keller / Max Scherzer: 34.6%

Once he gets ahead, Kirby does get his strikeouts, even though his strikeout-to-walk ratio is more about the "no walks" mentality than striking out the world. Seventy-five K's through half a season is nothing to sneeze at.

He can do that because his approach puts himself in a position to put hitters away … and then his stuff and command give him the ability to actually put those hitters away. Kirby is relentless and unapologetic: Get strikes. No walks. The results will fall into place.

"I don't want to take words out of his mouth -- but he'd rather give up a home run than walk a guy," Woodworth said. "He hates walking people. They have to earn it. That's probably the most upset I ever see him, is when he does walk a guy. He's different in that aspect. He hates free bases more than anybody I've ever met."