MLB Ump Watch
Ump Watch: The 2025 Run-Environment Board
Published
The archive keeps score on the men keeping score. These are the 2025 rolling-window run factors for home-plate umpires from our Retrosheet mirror, anything over 1.00 leaned toward offense, anything under leaned toward pitching.
There are 73 qualified names in the sample, spanning about 12 percent above average down to 14 percent below, a wider spread than most fans would guess.
The offense-friendly zones
Mark Wegner owns the most hitter-friendly environment in the sample: a 1.125 run factor across 71 games behind the plate, where scoring has run about 12 percent above the league norm.
Adrian Johnson (1.101 in 89 games) keeps the trend company.
Dan Bellino (1.097 in 96 games) keeps the trend company.
Where runs go to die
At the other extreme, Brennan Miller has squeezed scoring hardest: a 0.863 factor over 73 games, where scoring has run about 14 percent below the league norm.
David Rackley is nearly as stingy at 0.893 over 92 games.
At a glance
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 |
One more thing
Because every factor rides a rolling three-season window, the board moves slowly and honestly: no single series, however strange, can rewrite it.
None of this is about bad umpiring. Zones are simply different, and hitters and pitchers feel those differences long before the box score does.
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.