Umpire Grade · Blue Notes

Mark Wegner

26 games graded behind the plate.

Season Grade

93.1% ± 0.8

Avg Swing

runs / game

ABS Overturns

54/105 calls

3,810 correct of 4,092 graded takes (93.1% ± 0.8, 95%). Best game 96.4% · worst 88.2%. Grade is accuracy on taken pitches vs the rulebook zone; ABS is the Automated Ball-Strike System challenge record (how often the robots overruled the call).

What we can't say about Mark Wegner

This season is 4,092 graded takes, which puts Mark Wegner's overall accuracy at 93.1% ± 0.8 (95% interval). That is a real measurement against a league spanning about four points end to end. It is not enough for anything finer, and here is the arithmetic rather than our word for it:

how the zone moves with two strikes — about 818 takes, so ±1.7 points. (the league-wide two-strike effect is about 1 point in 2026.)
any single corner of the zone — about 341 takes, so ±2.7 points. (corner cells are where umpires actually differ.)
whether one pitcher is called tighter than another — about 68 takes, so ±6.0 points. (a given pitcher is worked once or twice a season.)

And a note on the number itself: an accuracy figure is a rate plus a convention for what counts as a miss. Ours grades every taken pitch against the rulebook zone as the feed reports it. Others are more forgiving — UmpScorecards counts a call wrong only when the pitch was at least 90% likely to be a strike — so two sites can print the same percentage about the same umpire and not mean the same thing by it. How the grade is built.

The overturn rate is a different kind of number and does not belong beside the grade: it is accuracy on the 105 pitches players chose to challenge, which are the pitches they already believed were wrong. 105 is enough to print it with its own denominator, which is what we do — but it still ranks umpires by how often they are appealed, not by how often they are right.

The road to the plate

The Road From Saint Paul

Mark Wegner went to umpire school at nineteen, spent seven years in the minor leagues, and has worked over 3,100 major-league games across more than two decades.

Mark Wegner was born on March 4, 1972, and grew up in Saint Paul, Minnesota. He went to umpire school at the age of nineteen, after he had started calling Little League games while in college in Minnesota. The school sent him into the minor leagues, where he spent seven years working his way up — through the Midwest League in 1993 and the Florida State League in 1994, and into the Pacific Coast League by 1998. On May 20 of that year, he worked his first major league game, in the National League. He joined the integrated MLB staff two years later, in 2000.

The assignments that followed put him on the field for Frank Thomas' 500th career home run, Randy Johnson's 300th career win, and a no-hitter thrown by Tim Lincecum. Through the 2026 season, he has umpired over 3,100 regular-season MLB games, with stints at all four positions — home plate, first base, second base, and third. He has also worked multiple playoff games, three World Baseball Classics, three World Series, and two All-Star Games — a big-league career spanning more than two decades.

In 2018, Wegner was promoted to crew chief, replacing Dale Scott, who retired after the 2017 season. He has described that elevation as the most fulfilling aspect of his career — because it allowed him to help other umpires perform at their best both on the field and off it.

He works behind the plate in 2026. The 19 games we have graded him this season sit on the record above.

Reporting: The Tablet, Baseball Almanac, BR Bullpen, Wikipedia. Umpire data: MLB StatsAPI, via the Fever engine.

By the Desk · filed 2026-07-24 — the profile reads as of its filing; the grading record above is live · every fact in this piece comes from a sourced research pack and clears an independent fact-check, and nothing is edited after filing.

The games

Game	Grade	Favor	ABS	Blue Note
KC @ TOR2026-08-27	A	0.6 KC	2/2	An honest evening's grade: nothing loud, nothing missed by much.
ATL @ MIN2026-08-18	A	0.3 ATL	2/3	Down the middle. Both dugouts had the same zone.
STL @ CHC2026-08-15	B+	0.5 STL	3/4	Reliable as a Tuesday: no complaints, no headlines.
HOU @ SF2026-08-10	C	0.3 SF	2/4	Expanded the plate a touch past its 17 inches.
DET @ SEA2026-08-06	C+	0.1 DET	3/4	Corner-to-corner and then some.
MIL @ LAA2026-08-01	B	0.8 MIL	0/3	You wanted a strike, you had to earn it twice.
BOS @ ATH2026-07-28	B	0.2 ATH	6/9	ABS had a long evening on this one.
PIT @ WSH2026-07-05	A-	0.0 WSH	1/4	Solid and unspectacular — exactly what the job asks.
CWS @ BAL2026-06-30	D	0.8 BAL	2/5	The zone stretched its legs.
SEA @ CLE2026-06-26	A	0.2 CLE	2/5	No notes. Well, one: nicely done.
SF @ MIA2026-06-20	B+	0.1 MIA	2/3	An honest evening's grade: nothing loud, nothing missed by much.
NYM @ CIN2026-06-15	A	0.0 CIN	1/5	Textbook top to bottom — a quiet masterclass.
NYY @ CLE2026-06-10	B+	0.3 NYY	3/5	The zone kept its promises.
TB @ MIA2026-06-06	C+	0.6 MIA	1/5	The zone had wings tonight.
TOR @ ATL2026-06-02	D	0.4 ATL	5/6	The players kept asking for a second opinion — and kept getting one.
SEA @ ATH2026-05-27	B	0.4 SEA	1/3	Squeezed the edges; the hitters didn't mind at all.
CLE @ PHI2026-05-24	B+	0.7 PHI	2/5	Called a fair game and let the players decide it.
BAL @ TB2026-05-19	A-	0.4 TB	1/3	The zone kept its promises.
MIN @ WSH2026-05-05	B+	0.0 MIN	1/2	Solid and unspectacular — exactly what the job asks.
PHI @ MIA2026-05-01	A	0.9 PHI	1/4	Reliable as a Tuesday: no complaints, no headlines.
BAL @ CLE2026-04-18	A	0.4 CLE	0/2	An honest evening's grade: nothing loud, nothing missed by much.
CHC @ PHI2026-04-14	B+	0.3 PHI	0/1	Down the middle. Both dugouts had the same zone.
WSH @ MIL2026-04-10	B	0.2 WSH	4/5	Solid and unspectacular — exactly what the job asks.
STL @ DET2026-04-05	B-	0.8 STL	5/7	The Automated Ball-Strike System put in some overtime here.
BOS @ HOU2026-03-31	A-	0.0 HOU	1/2	Called a fair game and let the players decide it.
CWS @ MIL2026-03-26	B+	0.3 MIL	3/4	Solid and unspectacular — exactly what the job asks.