How Much Do Umpires Matter in Baseball Handicapping?

The following post explores: how much do umpires matter in baseball handicapping?

Are MLB umpires really as important as many baseball bettors believe? It’s a fair question, especially when a few questionable calls can seem to change the entire course of a game.

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Every handicapper has to decide which information deserves the most attention. The key is separating factors that genuinely influence the outcome from those that simply receive a lot of attention.

Here’s what you need to know.

Overview

Baseball is one of the few sports where a single official directly influences every pitch. Since the home plate umpire determines balls and strikes, bettors have long tracked umpire tendencies in search of an edge.

Some umpires consistently call a larger strike zone, while others are known for giving hitters a little more room. Those differences can influence walk rates, strikeouts, pitch counts, and ultimately the number of runs scored during a game.

The question is not whether umpires matter—they clearly do. The more important question is whether their influence is significant enough to outweigh other handicapping factors such as starting pitching, bullpen strength, lineup quality, weather, and ballpark conditions.

What the Numbers Suggest

One way to measure an umpire’s influence is by comparing the earned run averages (ERAs) in games where each umpire is behind home plate. Since every umpire has slightly different tendencies, these numbers can provide a useful snapshot of how scoring has varied across the league.

The following examples from EV Analytics highlight the lowest and highest umpire ERAs. While they represent opposite ends of the spectrum, they also help illustrate an important point about the overall magnitude of umpire influence.

Lowest MLB Umpire ERAs (6/22/2024) – Source EV Analytics

Highest MLB Umpire ERAs (6/22/2024) – Source EV Analytics

Even when comparing the most pitcher-friendly and most hitter-friendly umpires, the gap is relatively small. The difference between the highest and lowest umpire ERAs is roughly 0.31 runs per game—less than one-third of a run.

While that difference is measurable, it suggests the overall impact of umpire assignments is fairly modest. Starting pitching, bullpen quality, lineup strength, weather, and ballpark conditions generally have a much greater influence on a game’s outcome.

This doesn’t mean bettors should ignore umpire assignments altogether. Instead, they are best viewed as a supporting variable that can reinforce an opinion rather than create one on their own.