Yes, MLB’s Strike Zone Is Shrinking. But Baseball Will Be Better for It

Okay, here’s a summary of the provided articles about the shrinking strike zone in MLB:

Multiple sources confirm that the MLB strike zone is effectively shrinking in the 2025 season, not due to a rule change in the definition of the strike zone itself, but rather due to a change in how MLB evaluates umpires.¹

The Change

• Previously, umpires were graded with a 2-inch “buffer zone” around the edges of the rulebook strike zone, meaning calls within this buffer weren’t penalized.
• For the 2025 season, this buffer zone has been reduced to just three-quarters of an inch on all sides.
• This tighter grading standard incentivizes umpires to call pitches closer to the actual rulebook definition of the strike zone, resulting in fewer strikes being called on pitches at the edges.

Impact and Observations:

• Fewer Edge Strikes: Pitchers are getting fewer strikes called on pitches at the edges of the plate, especially at the top and bottom of the zone.² One analysis suggests about one fewer edge strike per game.
• Increased Accuracy (Overall): Despite the complaints from pitchers and catchers about a shrinking zone, overall ball-strike accuracy in 2025 is reported to be the highest since Statcast began tracking. This is because umpires are making fewer incorrect calls outside the zone. However, accuracy on pitches inside the zone has reportedly decreased.
• Player Frustration/Surprise: Many players and managers claim they were not adequately informed about this change and are expressing frustration.
• Potential Benefits: Some argue that a tighter, more accurate strike zone (closer to the rulebook) is ultimately better for the game. It could lead to:
  • More walks, as borderline pitches are called balls.
  • A potential shift in offensive approaches.
  • A smoother transition towards the anticipated Automated Ball-Strike (ABS) system.
• Minimal Impact on Offense (So Far): Despite the change, overall offensive numbers (like batting average and runs per game) haven’t drastically changed compared to the previous year. Strikeout rates are even slightly down, and walk rates are up.

In essence, while the defined strike zone in the rulebook hasn’t changed, the enforced strike zone, due to stricter umpire grading, is smaller, leading to adjustments and opinions across the league.