MLB Ump Watch
Ump Watch, Which Umpires Tilted Totals in 2025
Published
Every home-plate umpire carries his own strike zone, and over enough games that zone becomes a run environment you can measure. From our Retrosheet archive, these are the rolling three-season run factors through 2025, where 1.00 means dead-league-average.
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.
Where the runs flowed
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.
Where runs go to die
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.
The board
The five most offense-friendly zones in the sample:
| 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.
Think of it as weather: nobody controls it, everybody plays in it, and only some people bother to check it before first pitch.
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.