MLB Ump Watch
Ump Watch: The 2025 Run-Environment Board
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.
All told, 73 umpires qualify for the board, and the gap between the extremes is real: about 12 percent above the norm at the top, 14 percent below at the bottom.
Friendly skies for hitters
Top of the board sits Mark Wegner at 1.125 across 71 games, where scoring has run about 12 percent above the league norm.
Next in line: Adrian Johnson, 1.101 across 89 games.
Next in line: Dan Bellino, 1.097 across 96 games.
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.
Close behind on the low end: David Rackley, 0.893 across 92 games.
The board
The over-leaning end of the board, in one look:
| 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 |
The fine print
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.
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.