Summary:
Trevor Williams was leading all MLB pitchers in fWAR outperformance early in 2024—and it wasn’t by accident. He dramatically increased his sweeper usage and saw immediate returns, vaulting into All-Star consideration before an untimely injury.
Before Training:
Williams had a low-usage sweeper (2.5%) that showed flashes but wasn’t yet a meaningful part of his arsenal. His fastball was low-spin, and lefties were giving him trouble. He needed something that gave him a chance to miss more bats—especially on his glove-side.
What We Worked On:
Sweeper Usage: Increased from 2.5% → 18%
Changeup Shape: Adjusted wrist position and pronation to improve outcomes vs. lefties
Approach Clarity: Focused on simplified execution and trusting what actually worked
Key Metrics:
Sweeper Whiff Rate (2024): Among the highest in MLB
K-BB% (Pre-Injury): 19.4%
fWAR Outperformance (Start of 2024): 1.6 fWAR above projection
All-Star Trajectory: Nearly locked in a spot before injury setback
Reflection:
Trevor bought into simplicity and stuck to the plan. The results were loud: higher whiffs, better outcomes to both sides of the plate, and a legitimate shot at national recognition. Even though injury got in the way, the adjustment itself was a clear win—and one that helped him pitch as well as anyone in the league before going down.
Videos / Content: