Hernandez claimed MLB has a history of discriminating against minority umpires, pointing out that as of the filing of his lawsuit, there had only been one minority crew chief in the league’s 150 years (Richie Garcia) — though that number has grown in the years since. There are 19 umpiring crews, each with four umpires, one of whom is a crew chief. In the appeal brief filed this week, seeking an overrule of the lower court judge’s dismissal, he also raised the argument that MLB not only looked the other way on its lack of diversity, but it altered the season-ending umpiring reports to justify this behavior.

“The District Court also failed to give appropriate weight to evidence of MLB’s disparate treatment of Mr. Hernandez, including evidence that MLB was manipulating the performance of Mr. Hernandez and other minority umpires to make their performances look worse,” the umpire argued in the court filing.

MLB during the time period covered in the complaint, 2011-16, performed midseason reviews of umpires called umpire evaluation reports (UER), and followed with year-end reviews. Hernandez said his UERs were glowing, but when it came time for his year-end review, the results did not reflect the previous positive assessments.

“[A] review of Mr. Hernandez’s Year-End Evaluations and his UERs for the years 2011-2016 reveals that MLB manipulated Mr. Hernandez’s year-end evaluations in order to make his job performance appear worse than it actually was,” he argued. “Mr. Hernandez’s Year-End Evaluations for the 2011-2016 seasons do not even come close to accurately summarizing Mr. Hernandez’s actual performance in those seasons.”

Here’s how the league’s system works, according to sources: MLB employs a team of auditors to assist in its review of each game. The auditors set a unique strike zone for each player based on his setup in the batter’s box. The top of the strike zone is his beltline and the bottom the hollow of his back knee, both determined when he’s loading and preparing to swing. The margin of error is implemented off the corners—2 inches on each side of the plate.

The rationalization for the margin of error, which was collectively bargained between the league and the umpires’ union—the MLB Umpires Association declined comment—was ostensibly due to the limitations of previous tracking technology but also buys umpires leeway in their grading. MLB currently employs a camera-based system to track its games, and it provides a wide array of data now seen as standard across baseball. Pitch velocity and movement, batted-ball exit velocity and launch angle—each is measured by the 12-camera Hawk-Eye system installed in all 30 major league stadiums. While Hawk-Eye’s margin of error is measured to be .16 of an inch, previous systems’ was greater, and the umpires negotiated a so-called buffer zone of 2 inches on either side. Even with Hawk-Eye, that remains in place.

Furthermore, the umpires’ union created a Zone Enforcement committee to double-check incorrect calls and file appeals to have the scoring of pitches reviewed. In 2021, about 30% of the pitches appealed, including those in which a pitcher misses his spot but still lands a ball in the strike zone to a scrambling catcher, were overturned.

With those parameters in place, the league breaks down pitches into three categories: “correct” calls, “acceptable” calls within the so-called buffer zone and “incorrect” calls. By MLB’s calculations, the league-wide average for umpires on correct and acceptable calls—belt to knees, 21 inches across (the 17-inch-wide plate plus 2 inches either way)—was 97.4% in the 2021 season. The highest-ranked umpire, according to MLB, graded out at 98.5%. The lowest: 96%.

These numbers do not square with the metrics provided by independent evaluators. UmpScores said the best home-plate umpire in baseball last year, Tripp Gibson, graded out around 93.6% accurate. Four umpires last season, according to UmpScores, missed on more than 10% of pitches they called for balls and strikes.

TruMedia, an analytics company that provides data to ESPN, has metrics that measure correct-call percentage and adjusted correct-call percentage. Leaguewide this season, according to TruMedia, MLB umpires have called 92% of pitches correctly. With its adjusted metric, which penalizes particularly egregious calls in a similar fashion to MLB’s system, TruMedia bumps that number to 96.24%—close to in line with the league’s internal measurement.