Mark Carlson
With Mark Carlson behind the plate, MLB games average 8.8 total runs versus a league average of 9.02. That is a run factor of 0.89, #90 of 96 umpires for scoring, making him a pitcher's umpire, one of the tightest run-suppressing zones.
A strikeout factor of 0.97 (-3%) reflects how wide or tight Mark Carlson calls the zone. A wider zone means more called strikes, more strikeouts, and fewer baserunners, which is why umpire run and strikeout factors usually move together. The home team wins 52.5% of his games, close to the league's modest home rate.
From 40 games with Mark Carlson as home-plate umpire, rebuilt nightly. Factors are normalized so 1.00 equals the league-average umpire. A single umpire is a small slice of the season, so read the extremes as tendencies, not certainties. Descriptive, not a prediction.
Last recomputed August 23, 2026.