Don’t extrapolate outside the bounds of your data. Outliers tend to revert towards the mean. Gee, thanks a lot, Mr. Gilliam — how am I supposed to explain Christopher Sanchez using those two rules?
Sánchez has made a habit of forcing analysts to ask that question. He was the biggest breakout of 2025, and he has kept climbing in 2026, with only nine pitchers lowering their SIERA more and only 11 lowering their FIP more than he did from 2025 to 2026. The same pattern showed up in strikeout-to-walk rate, where only six pitchers improved more over that span. Go back one year further and the numbers look even louder: from 2024 to 2025, no pitcher who threw even 100 innings lowered his SIERA more, only three pitchers lowered their FIP more, and no pitcher improved his K-BB% more.
That is the shape of a true breakout. It is also why Sánchez has become such a clean test case for what advanced pitching metrics can and cannot tell you. ERA can swing on sequencing, defense and luck; SIERA and FIP are supposed to be steadier, and Sánchez has still outrun the field in both of them across back-to-back seasons. In other words, this is not just a pitcher getting credit for noise. It is a pitcher repeatedly moving the underlying numbers that are supposed to strip the noise away.
The surprising part is how little the Arsenal has changed while the results keep getting better. The pitch models say Sánchez’s arsenal is shockingly stable. Both models think all three of his pitches are about as good as they were last year, and his usage rates on each pitch are roughly unchanged. That matters because it takes away the easy explanation that he rebuilt himself through a dramatic new pitch mix or a sudden jump in raw stuff.
Instead, the gains point to something subtler. Sánchez has followed in Zack Wheeler’s footsteps by differentiating his approach against lefties and righties, leaning into the kind of matchup-based planning that can change a pitcher’s effectiveness without changing the radar gun or the repertoire. That sort of adjustment can be easy to miss because it does not look like reinvention. It looks, from a distance, like the same pitcher. The numbers say otherwise.
That is why Sánchez keeps confounding the tidy rules of projection. If outliers tend to drift back toward the middle, he has spent two seasons moving farther away from it. The bigger question is no longer whether 2025 was a fluke. It is how long he can keep pushing the ceiling while throwing essentially the same 3 pitches in essentially the same proportions.
