A long time ago, Bill wrote
an essay trying to determine which pitching statistics are most aligned with value:
Which pitching stats are most closely connected to value? Suppose that you know two facts about two pitchers: each pitcher’s ERA, and his won-lost record. Suppose that the two disagree; one pitcher has the better won-lost record, but the other has the better ERA. Which one is more likely to be the better pitcher in fact? Suppose that you know his strikeouts, or his walks. Which would you rather have?
I’ve left the double-spaces in after the period, just to make sure you know that’s Bill’s voice up there, and not me trying to imitate the master. In his
second essay, Bill concluded that the metric that
most correlates to a pitcher’s value – better than strikeout rate or winning percentage or adjusted ERA – is strikeout-to-walk ratio.
Bill wrote those essay all the way back in 2014, and it took me a little while to find them. But I’m glad I did, because the central conclusion is one that’s resided in the back of my mind ever since I encountered it, just waiting for a moment to come back to it.
And Mariners starter George Kirby is giving me the chance to dust off the cobwebs.
* * *
Let’s cast a glance, first, at the best-ever pitching seasons, by strikeout-to-walk ratio:
|
Pitcher
|
Year
|
K/BB
|
IP
|
|
Phil Hughes
|
2014
|
11.62
|
209.2
|
|
Bret Saberhagen
|
1994
|
11.00
|
177.1
|
|
Cliff Lee
|
2010
|
10.28
|
214.2
|
|
Curt Schilling
|
2002
|
9.58
|
259.1
|
|
Marco Gonzales
|
2020
|
9.14
|
69.2
|
|
Pedro Martinez
|
2000
|
8.88
|
217
|
|
Greg Maddux
|
1999
|
8.85
|
232.2
|
|
Pedro Martinez
|
1999
|
8.46
|
213.1
|
|
Ben Sheets
|
2004
|
8.25
|
237
|
|
Max Scherzer
|
2015
|
8.12
|
228.2
|
I have summarily eliminated three men from consideration on this list: the 1883 and 1884 seasons of Grasshopper Jim Whitney, hurler George Bradley’s 1880 campaign for the Providence Grays, and Handsome Henry Boyle’s rookie season for the St. Louis Maroons of the Union Association. I have eliminated Whitney and Bradley from consideration because their seasons occurred so long ago that they do not have relevance in a consideration of a current player. I eliminated Boyle because he’s about as handsome as, well, a Boyle.
The remaining list of pitchers is terrific, of course. Bret Saberhagen, Pedro Martinez, Greg Maddux, and Max Scherzer all won multiple Cy Young Awards. Cliff Lee won one award, and Curt Schilling might’ve netted a couple if he hadn’t have the misfortune of having to compete on end-of-the-year-awards-ballots with teammate Randy Johnson.
Ben Sheet and Phil Hughes had lesser careers, but they were both extremely touted prospects who had moments of success. Ben Sheets was an excellent pitcher every time he took the hill, but he had a bad back from the outset, and never had the chance to pitch without pain. He would have been great.
Phil Hughes: when I think of Hughes I think of a career that was forced. There were lofty expectations put on Hughes from the outset, and in a career that unfolded in the cauldron of the Bronx, he just kept trying to reach those expectations. My sense is that he would have had a different career if he had been drafted by a different organization, that he might’ve found a better equilibrium between trying to figure out how to be a pitcher, and trying to figure out how to turn into the next Roger Clemens overnight. Anyway, Hughes’ season happened after he escaped the Evil Empire.
Marco Gonzales doesn’t really belong here: he had a strong quarter-season during the COVID year, so we’re obligated to credit him.
So what does this have to do with George Kirby?
* * *
Last year, George Kirby had an excellent strikeout-to-walk ratio. In 130 innings, he struck out 133 hitters while walked only 23, good enough for a ratio of 6.05 strikeouts per walk allowed.
That’s an excellent mark for any pitcher. It is a really excellent mark for a rookie pitcher.
Here’s how Kirby sat among the qualified pitchers from last year:
|
Rank
|
Pitcher
|
K-to-BB
|
|
1
|
Aaron Nola
|
8.10
|
|
2
|
Kevin Gausman
|
7.32
|
|
3
|
Corey Kluber
|
6.62
|
|
4
|
Justin Verlander
|
6.38
|
|
-
|
George Kirby
|
6.05
|
|
5
|
Shane Bieber
|
5.50
|
|
6
|
Yu Darvish
|
5.32
|
|
7
|
Max Fried
|
5.31
|
|
8
|
Gerrit Cole
|
5.14
|
|
9
|
Shane McClanahan
|
5.11
|
|
10
|
Shohei Ohtani
|
4.98
|
You see the same correlation between pitching excellence and strikeout-to-walk ratio in this leaderboard. Kluber, Verlander, and Beiber have all won Cy Young Awards. Cole, Nola, Darvish, and Guasman have been annual contenders. McClanahan, Ohtani, and Fried are in the early stages of their career, but there are no slouches on this list: these are strong pitchers.
Last year, George Kirby ranked right in the middle of them.
And this year?
So far in 2023, George Kirby has 35 strikeouts and three walks, for a ratio of 11.67 strikeouts-per-walk.
That single-season list again:
|
Pitcher
|
Year
|
K/BB
|
IP
|
|
Phil Hughes
|
2014
|
11.62
|
209.2
|
|
Bret Saberhagen
|
1994
|
11.00
|
177.1
|
|
Cliff Lee
|
2010
|
10.28
|
214.2
|
|
Curt Schilling
|
2002
|
9.58
|
259.1
|
|
Marco Gonzalez
|
2020
|
9.14
|
69.2
|
|
Pedro Martinez
|
2000
|
8.88
|
217
|
|
Greg Maddux
|
1999
|
8.85
|
232.2
|
|
Pedro Martinez
|
1999
|
8.46
|
213.1
|
|
Ben Sheets
|
2004
|
8.25
|
237
|
|
Max Scherzer
|
2015
|
8.12
|
228.2
|
Only three pitchers in the World Series era of baseball’s history have ever posted strikeout-to-walk ratios higher than 10. Only five pitchers have had a ratio better than 9.0, and one of those five did so in a pandemic-shortened third-of-a-season. George Kirby is flirting with a ratio of 12.0.
It is unlikely, of course, that Kirby will continue on this pace: he’s pitched 44.2 innings this year, which means he’s a quarter of the way through the race. It’s unlikely that he’ll maintain his pace.
But George Kirby remains an anomaly.
Here’s that list again, with each pitcher’s age during their elite K-to-BB seasons, and the number of major league innings they’d logged prior to their seasons:
|
Pitcher
|
Year
|
K/BB
|
Age
|
Prior MLB IP
|
|
George Kirby
|
2023
|
11.67
|
25
|
130
|
|
Phil Hughes
|
2014
|
11.62
|
28
|
780.2
|
|
Bret Saberhagen
|
1994
|
11.00
|
30
|
1897.1
|
|
Cliff Lee
|
2010
|
10.28
|
31
|
1196.2
|
|
Curt Schilling
|
2002
|
9.58
|
35
|
2158.2
|
|
Marco Gonzalez
|
2020
|
9.14
|
28
|
447
|
|
Pedro Martinez
|
2000
|
8.88
|
28
|
1359.1
|
|
Greg Maddux
|
1999
|
8.85
|
31
|
2365.2
|
|
Pedro Martinez
|
1999
|
8.46
|
27
|
1146
|
|
Ben Sheets
|
2004
|
8.25
|
25
|
588.2
|
|
Max Scherzer
|
2015
|
8.12
|
30
|
1239.1
|
All of the pitchers who have posted elite strikeout-to-walk ratios did so in the middle of their careers, with a decent amount of major league innings under their belt. The average age in that group is 29.3, and their average tally of innings tossed in the majors is 1317.
Even the youngest players – Ben Sheets and Marco Gonzales – had significant experience. Sheets had three full seasons before 2004. Marco Gonzales has the fewest career innings logged, but he was twenty-eight years old and in his sixth season in the majors when 2020 rolled around.
Historically, having really elite strikeout-to walk rates is the realm of the established pitcher, for very obvious reasons. It is possible to generate a lot strikeouts with terrific stuff, and it is possible to have exceptional control. But is it exceedingly difficult to stay in the zone while avoiding contact.
But George Kirby breaks the mold: he is only twenty-five years old, and he has logged only 130 innings in the majors. But he is performing, in 2023, with all the savvy and sophistication of a mid-career Bret Saberhagen or Greg Maddux.
Is he rare?
What he’s doing is actually unprecedented. Baseball has never seen a young pitcher with such an elite strikeout-to-walk ratio.
Here are the best strikeout-to-walk ratios of qualified starting pitchers through their Age-25 seasons:
|
Rank
|
Pitcher
|
K/9 Thru Age 25
|
|
1
|
Shane Bieber
|
5.94
|
|
2
|
Noah Syndergaard
|
4.94
|
|
3
|
Kevin Slowey
|
4.90
|
|
4
|
Chris Paddack
|
4.77
|
|
5
|
Satchel Paige
|
4.54
|
|
6
|
Walker Buehler
|
4.52
|
|
7
|
Stephen Strasburg
|
4.49
|
|
8
|
Chris Sale
|
4.26
|
|
9
|
Madison Bumgarner
|
4.22
|
|
10
|
Jose Fernandez
|
4.21
|
|
11
|
Roy Oswalt
|
4.00
|
This is a good list. All of these pitchers were terrific young pitchers on Hall-of-Fame trajectories. If you go further down, you get Nola and Hamels and Cole and Ben Sheets and Roger Clemens. A strikeout-to-walk ratio of 3.5 or 4.0 or 5.0 is very impressive for a young pitcher.
George Kirby’s career strikeout-to-walk ratio is 6.72. He is ahead of Shane Bieber by nearly a strikeout-per-walk, the same gap that Beiber has over the rest of the pack.
Of course, that is a list of qualified pitchers, and Kirby isn’t a qualified starting. Surely there are young pitchers who have comparable rates over 150 innings.
No, there aren’t. If you drop the innings requirement to 150, you get George Kirby at the top:
|
Rank
|
Name
|
K-to-BB
|
|
1
|
George Kirby
|
6.72
|
|
2
|
Roberto Osuna
|
6.33
|
|
3
|
Shane Bieber
|
5.94
|
|
4
|
Emmanuel Clase
|
4.97
|
|
5
|
Noah Syndergaard
|
4.94
|
|
6
|
Kevin Slowey
|
4.90
|
|
7
|
Josh Hader
|
4.85
|
|
8
|
Chris Paddack
|
4.77
|
|
9
|
Edwin Diaz
|
4.65
|
|
10
|
Craig Kimbrel
|
4.65
|
|
11
|
Rod Beck
|
4.63
|
|
12
|
Spencer Strider
|
4.61
|
The other additions to the list are a bunch of closer (Osuna, Clase, Hader, Diaz, Kimbrel, Beck), and starters Kevin Slowey, Chris Paddack, and Spencer Strider.
So George Kirby has a case for having the best strikeout-to-walk ratio of any young pitcher in baseball history. No young pitcher has ever managed the strike-zone while yielding strikeouts better than George Kirby.
I don’t think anyone has noticed this. Partially, this is because George Kirby doesn’t have any of the flashy attributes that typically garner our attention. Kirby throws hard, but he does not have a blistering fastball that sits at 101. He is tall-but-slight, but he’s not that tall, and he doesn’t seem to throw with maximum effort. He secondary stuff is strong, but not eye-popping. He plays in Seattle, which means that a lot of people are asleep before he steps onto the mound.
I don’t think George Kirby would’ve made any pundit’s list of top-twenty pitchers in baseball at this season’s outset, and I don’t know that he’s made many top-20 lists right now. He sits in a gray area: he hasn’t pitched enough to rate among the established elites in the game, and he isn’t discussed when the conversation focuses on early-career starting pitchers.
But judged by the metric that most correlated to success as a pitcher – judged by strikeouts-to-walks – George Kirby is performing at a level that baseball has seldom seen from any pitcher, and has never seen from a pitcher so young.
If you’re not paying attention to George Kirby, you should be.
David Fleming is a writer living in western Virginia. He welcomes comments, questions, and suggestions here and at dfleming1986@yahoo.com.