Vincent Carchietta-Imagn Photos
In 2023, Mets left-hander David Peterson struck out 128 batters in 111 innings. Peterson’s strikeout charge that 12 months, 26.0%, was twenty seventh within the league out of 127 pitchers who threw 100 or extra innings. He was tied with Zac Gallennot far behind Luis Castillo, Gerrit Coleand Zack Wheeler.
The following 12 months, Peterson’s strikeout charge dropped by greater than six factors, to 19.8%, however he shaved three-quarters of a run off his FIP, and greater than two runs off his ERA. This 12 months, Peterson is hanging out 21.5% of opponents, and after Wednesday night time’s complete-game shutout of the Nationals, his ERA is 2.49, which is 14th amongst certified starters.
However I believed hanging batters out was good! How did Peterson flip into this unhittable monster whereas working a decrease strikeout charge than Shane Baz?
Effectively, the strikeout factor, it seems, by no means actually suited Peterson all that effectively. In 2023, he was working exterior the strike zone, making an attempt to get batters to chase. He isn’t a tough thrower; his two fastballs principally work within the 91-93 mph vary. The 6-foot-6 Peterson does get a bit of bit of additional zip — or perceived zip, anyway — due to Ninety fifth-percentile extension, however he’s not gonna blow hitters away.
Nor was he getting hitters to chase; his O-Swing% in 2023 was 28.8%, bang-on league common.
In the meantime, when Peterson was working inside the zone, hitters weren’t getting fooled both. Right here’s the warmth map from the 2023 for Peterson’s two fastballs (his four-seamer and sinker) to left-handed hitters:
Now, look. I don’t have all of the solutions, and that is only a idea, so take it for what it’s price. However I believe that throwing 91 mph fastballs down the center goes to result in plenty of laborious contact.
Not less than, that’s what occurred to Peterson in 2023. Lefties hit .264 in opposition to his fastballs, with an xBA of .277. They had been much more relentless in opposition to breaking pitches, in opposition to which they hit .319. General, Peterson obtained tagged with an opponent wOBA of .357 (which is precisely Bryce Harper’s wOBA in 2025), and an xwOBACON of .416, which was within the backside 5% of the league.
A pitcher who permits that high quality of contact had higher miss plenty of bats, and Peterson didn’t actually. His chase and whiff charges had been each good, however not nice, in 2023. The outcome: an ERA over 5.00.
Effectively, dangling the baseball exterior the strike zone didn’t work, so let’s strive one thing totally different:
Zone Time for David Peterson
Yr
Zone%
O-Swing%
Z-Swing%
Contact%
P/BF
P/Out
2023
46.0%
28.8%
64.6%
72.7%
4.00
5.91
2024
49.4%
29.4%
66.0%
77.0%
3.68
5.17
2025
50.7%
31.5%
62.7%
77.6%
3.75
5.18
Beginning in 2024, Peterson started throwing the ball within the zone extra. His in-zone charge has jumped about 4 factors for breaking balls, and an unbelievable 10 share factors for fastballs, from 2023 to 2025.
The obvious impact of this new strategy is that Peterson’s stroll charge dropped from 10.2% in 2023 to 9.0% in 2024, and seven.6% this 12 months. Throw within the zone extra, subject fewer walks. That is smart. He’s additionally gotten extra environment friendly; every batter confronted is costing Peterson 1 / 4 of a pitch much less now than it did in 2023. Every out prices three-quarters of a pitch much less; two years in the past, 100 pitches obtained Peterson 17 outs. Now that many pitches get him 19.3 outs. That’s the distinction between 5 2/3 innings and 6 1/3 innings per begin.
What’s barely much less intuitive is that the place Peterson was getting lit up on contact in 2023, he’s dwelling with contact significantly better now. Opponents can nonetheless hit the ball laborious — his hard-hit charge is 46.3% this 12 months, which is fairly unhealthy out of context and really up a pair ticks from 2023 — however they’re not doing as a lot harm.
Peterson has turn out to be superb at preserving the ball off the barrel of the bat, and due to this fact limiting the affect, so to talk, of laborious contact. In his shutout victory over Washington, Peterson obtained simply 13 whiffs on 50 swings — a fairly pedestrian whole, particularly for a begin of that high quality. He additionally allowed 13 batted balls with an exit velo of 93 mph or extra — simply over half the 25 balls put in play in opposition to him.
However solely a type of 13 screamers got here off the bat at a launch angle between 15 and 50 levels. (That one, an eighth-inning double by Luis García Jr.was Washington’s solely extra-base hit of the day.)
Peterson doesn’t miss that many bats, and it’s not particularly tough to hit the ball laborious in opposition to him. However laborious contact isn’t a lot good when it leads to a groundout or a medium-depth fly ball or, at most, a single. It’s laborious to construct an enormous inning by stringing collectively singles.
After I see a pitcher change his output to this extent, particularly when he pairs a decrease strikeout charge with higher total numbers, I often anticipate to see a change in repertoire. A swap from a slider to a sweeper, a reworked changeup, or (tosses 1 / 4 within the swear jar) a brand new cutter.
Not Peterson. He’s nonetheless throwing the identical 5 pitches on the identical velocity, with about the identical spin charges and motion profiles.
What I’ll say is that Peterson is throwing his varied pitches, and particularly his two breaking balls, with a lot better consistency.
Again when he was making an attempt to bait hitters to chase, Peterson splashed his slider mainly wherever mid-zone and beneath, and the motion was form of everywhere. Right here’s how Peterson’s two breaking balls moved in 2023:
And right here they’re in 2025:
The slider particularly is rather more exact. So exact I instinctively wish to name it sharper, although it’s not, actually. It doesn’t have exceptional motion in both route. However with extra constant motion, Peterson will be extra exact in the place he throws it. Right here’s the place the slider ended up in 2023:
And right here’s the place he’s throwing it this 12 months:
Whereas opponents tagged Peterson’s slider for a .355 wOBA in 2023, they’re solely wOBAing .225 this 12 months. A legal responsibility when thrown as a chase pitch, the slider is a significant asset now that Peterson’s throwing it for strikes.
See? You don’t should throw laborious or rip off large spin charges in spite of everything. You simply should throw strikes.
