Back in October, my analysis “Mark Vientos: Simplified Power, Compact Efficiency” made the case that Vientos’s next developmental step was to “Learn How to See.”
Since Vientos remains on the roster as a high-upside player for the 2026 team, we need to drill down on why his 2025 season went sideways. After a breakout 2024 and a sharp regression in 2025, the popular explanation has been that Vientos became too passive—that he was taking too many good pitches early, falling behind, and then collapsing.
I reviewed the swing data alongside my previous mechanical breakdown to test this hypothesis. The findings are conclusive: Vientos possesses a "short, direct, and efficient" swing with a "connected" kinetic chain. He didn't slump because of his mechanics or passivity. He slumped because the league exposed his specific weakness in "secondary pitch recognition."
1. The Data Rejects the "Passive" Hypothesis
Vientos did not stop swinging. The data shows he was actually more aggressive in 2025 than during his breakout 2024 campaign, both on the first pitch and on pitches within the strike zone.
Table 1: The Aggression Metrics
Source: Baseball-Reference / Baseball Savant (Plate Discipline & Swing Stats)
The Reality: Vientos increased his aggression on the first pitch (30.6% to 32.8%) and attacked pitches inside the strike zone more frequently (Zone Swing % rose to 70.8%).
The problem was not intent; it was outcome. In 2024, his early aggression resulted in an elite 1.047 OPS. In 2025, that plummeted to .631. As I noted in my initial scouting report, his "sequencing" is solid and capable of "repeatable contact", yet the results dropped. This indicates he was swinging at "pitcher's pitches" on the edges rather than mistakes over the heart of the plate.
2. The Funnel: How One Missed Decision Becomes No Good Options
The hypothesis that Vientos struggles with two strikes is correct—but that is a symptom, not the cause.
My assessment of his Zone Coverage is that it remains "Limited", meaning he needs expanded plate awareness to sustain power. In 2024, he hid this weakness by doing damage early. In 2025, because his early aggression resulted in weak outs or fouls, he was funneled into pitcher-friendly counts at a much higher rate.
Table 2: The Funnel to Failure
Source: Baseball-Reference Splits
How to Read This: "sOPS+" measures a player relative to the league average (100). In 2024, Vientos was near-average at surviving 0-2 counts (82 sOPS+). In 2025, he found himself in that terminal count nearly 50% more often (57 times), and he was significantly easier to put away (70 sOPS+).
3. The Smoking Gun: The Fastball Paradox
This is the most critical finding in the data. The collapse in 2025 was driven by a sudden inability to punish the fastball—but not because he was missing it.
Table 3: Fastball Performance & Contact Quality
Source: Baseball Savant Pitch Tracking & Quality of Contact
The Insight: Vientos actually whiffed less on fastballs in 2025 (23.6%) than he did in 2024 (26.7%).
However, his Barrel % dropped significantly (14.1% to 11.5%). When a lower whiff rate combines with plummeting Slugging Percentage (.615 to .441), it signals weak contact. His biomechanical analysis identifies his contact plane as "steep-to-neutral", which naturally generates lift. When his timing is disrupted, this plane results in pop-ups or weak fly balls rather than line drives.
4. The Trap: Sinkers and Sweepers
Why was his timing off? The data validates my diagnosis regarding "spin deception”.
What is Run Value? Run Value measures the run expectancy added (or lost) by a player on every pitch. A positive number means production; a negative number means the hitter decreased the team's chance of scoring.
In 2025, pitchers stopped challenging Vientos with honest 4-seamers and started tunneling pitches that looked like fastballs but moved late.
• Sinker Run Value (2025): -5
• Sweeper Run Value (2025): -5
Both the Sinker and Sweeper are designed to mimic the 4-seam fastball out of the hand. The fact that Vientos posted a -5 Run Value against both confirms the need to improve "curveball/slider differentiation".
Conclusion: Harmonizing the Sequence
The data proves that the 2025 slump was not about passivity, nor was it a mechanical breakdown. My analysis confirms his lower-half usage is "Strong" and his kinetic chain is "Connected".
The issue is (visual) information dependence. In 2024, Vientos crushed fastballs because he saw them clearly. In 2025, the league adjusted by disguising fastballs with Sinkers and Sweepers.
The Fix: The path forward is not a swing overhaul. As I outlined previously, the focus must be on "approach refinement" rather than mechanical change. The challenge for the Mets' hitting lab is "harmonizing the body’s sequence and the brain’s recognition window".
If Vientos can "Learn to See" and lay off the Sinker/Sweeper tunnel early in the count, his simplified power will play again.
3 comments:
Well, as someone that has always rooted for players most others want to get rid of, I hope Vientos can re-adjust to the adjustment the league made.
But, is it only recognition? In 2024, Vientos seemed happier playing. He was the last cut in spring training after having a 35% strikeout rate but leading the team in HR when the Mets signed JD Martinez. But, when he got promoted, he played third base and hit. Last year, he wasn’t in the field as often and as for hitting, well… sometimes. He never seemed relaxed of in a good groove. That player that was punishing the Dodgers in the playoffs is still there and I’m glad he has a GM like Stearns that doesn’t read the papers, because most others would have sent him to San Diego for Laureano by now.
I’m very familiar with this subject. And disagree.
Going from 30% to 32% on first pitches is in and of itself very conservative. Brent Rooker was floundering as a professional into his late 20s, and then started swinging at a very high rate on first pitches and went from reject to Star. Simply put, and I’ve mentioned this a number of times, Vientos got to two strike, counts in53% of his plate appearances.. In those 53% of his plate appearances, he hit an bysmal .133. So, if I’m a doctor writing him a prescription, I’d be telling him to take that rate up to 45% or even on first pitches, because getting to two strikes is clearly a devastating place for him to be. His .133 in those 53% of plate appearanceswas accompanied by a very low on base percentage and a very low slugging percentage. Basically, in those 53%, he hit like Jerry Koosman. If I were Mark, which I’m not, I would follow my prescription. He might just be the next Brent Rooker.
He also fanned 115 times in the 248 times he got to 2 strikes. How many plate appearances and strikeouts would occur if he was much more aggressive on strike one? Mathematical logic would dictate that both numbers would become a smaller relative proportion of his total plate appearancesIf you’re only swinging it two pitches, rather than three, my guess is you’re going to shrink out more. He is not JuanSoto, part of whose skills include an amazing ability to work out walks in large numbers. So, MV just can’t take pitches the way Soto can and be successful.
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