MLB Players Measured More Precisely Under New Rules

New Automated Ball-Strike Challenge System requires standardized height measurements

Mar. 21, 2026 at 2:12am

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Major League Baseball has implemented new rules surrounding player height measurements, leading to some players being listed as shorter than previously reported. The changes are part of the league's implementation of the Automated Ball-Strike Challenge System (ABS), which requires precise measurements to accurately determine each player's strike zone. Teams must now record player heights between 10 a.m. and 12 p.m. local time to prevent shrinkage throughout the day, and the measurements are taken with medical-grade instruments with multiple readings averaged together.

Why it matters

The new height measurement rules are intended to ensure fairness and consistency in the ABS system, which can overturn calls based on fractions of an inch. Precise player heights are crucial for accurately defining each batter's personal strike zone.

The details

Under the new rules, players must be measured without hats, shoes, or slouching, with their knees exposed and heels together. Teams record the measurements between 10 a.m. and 12 p.m. local time to prevent daily height fluctuations. League officials take two measurements and average a third if there is more than a few millimeters of inconsistency.

  • The new height measurement rules were implemented at the start of the 2026 MLB season.

The players

Gavin Lux

Tampa Bay Rays infielder who was previously listed at 6 feet 2 inches but is now measured at 5 feet 11 inches.

Bo Naylor

Cleveland Guardians catcher who dropped from 6 feet to 5 feet 9 inches in the new measurements.

Connor Wong

Boston Red Sox catcher who is now listed at 5 feet 11 inches, down two inches from last season.

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What they’re saying

“People shrink over the course of a day. I'm not entirely sure how much, but I've been told that enough times to believe that it is scientifically true.”

— Will Hudgins, Brewers Assistant GM

“It was very detailed. You can tell they have done this in the Minor Leagues and have thought about every part of this.”

— Will Hudgins, Brewers Assistant GM

What’s next

Each ballpark will have a measuring device for players called up during the season, with a member of the home team's medical staff being the official measurer.

The takeaway

The new height measurement rules are part of MLB's efforts to ensure fairness and consistency in the Automated Ball-Strike Challenge System, which can overturn calls based on fractions of an inch. While some players are seeing their listed heights decrease, the standardized process is intended to provide a more accurate representation of each player's physical attributes.