MLB Ump Watch
Ump Watch, Which Umpires Tilted Totals in 2025
Published
Some zones are cathedrals and some are closets, and the hitters know which is which long before the numbers do. Our Retrosheet build keeps score anyway: 2025 rolling run factors per home-plate umpire, with 1.00 meaning perfectly neutral.
The sample covers 73 umpires with enough games behind the plate to matter, and the environments range from roughly 12 percent above league average at one end to 14 percent below at the other.
The offense-friendly zones
The friendliest zone belongs to Mark Wegner, 1.125 over 71 games calling balls and strikes, where scoring has run about 12 percent above the league norm.
Adrian Johnson is right behind at 1.101 over 89 games.
Dan Bellino (1.097 in 96 games) keeps the trend company.
The tight zones
The stingiest zone belongs to Brennan Miller: 0.863 over 73 games behind the plate, where scoring has run about 14 percent below the league norm.
David Rackley (0.893 in 92 games) rounds out the pitching-friendly wing.
By the numbers
Here are the top five run environments, highest factor first:
| Umpire | Run factor | Games |
|---|---|---|
| Mark Wegner | 1.125 | 71 |
| Adrian Johnson | 1.101 | 89 |
| Dan Bellino | 1.097 | 96 |
| Mike Muchlinski | 1.093 | 86 |
| Chris Guccione | 1.091 | 79 |
Worth remembering
These factors are built on rolling three-season windows, which is long enough to mean something and short enough to notice when a zone genuinely changes.
The spread is the story: a few points of run factor is the difference between a park that plays over and one that plays under, except this park travels with the umpire from city to city.
These are historical tendencies from seasons past, not tonight's assignments, treat them as trivia about the shape of the sport, not a betting signal on any specific game.