Let me tell you what is happening to the four-seam fastball. Or rather, what is not happening, and why that is the problem.
Velocity is up across the board. The average fastball is harder than it has ever been. And yet, the four-seam is getting crushed at historic rates. How do you reconcile that?
You do not. You understand that velocity and effectiveness are different things, and that the league has caught up to the high spin, high ride fastball in a way that should have every pitching development person rethinking their whole approach.
The data is not subtle here.
High ride fastballs, those elite vertical break pitches that used to generate pop-ups and swinging strikes up in the zone, are getting squared up. Hitters have adjusted their launch angles. They have leveled out their swings to match the pitch plane. The thing that made that fastball devastating five years ago is now a feature, not a bug, for the hitter attacking it.
What is working now? Arm-side run. Cut. Movement that the eye has trouble tracking because it does not behave like a "fastball" in the traditional sense.
Spencer Strider has a cutter. Zack Wheeler leans on run. The guys at the top of the effectiveness charts are not the ones with the flattest approaches and the most vertical drop. They are the ones with movement that disrupts timing, not just ride that beats barrel recognition.
This is not a complicated story. It is just the story the four-seam partisans do not want to tell.
Adapt or get hit hard. That is the pitch design message for 2025 and beyond.