Alfonso Márquez
25 games graded behind the plate.
3,625 correct of 3,925 graded takes (92.4% ± 0.8, 95%). Best game 95.4% · worst 89.9%. 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 Alfonso Márquez
This season is 3,925 graded takes, which puts Alfonso Márquez's overall accuracy at 92.4% ± 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 785 takes, so ±1.9 points. (the league-wide two-strike effect is about 1 point in 2026.)
- any single corner of the zone — about 327 takes, so ±2.9 points. (corner cells are where umpires actually differ.)
- whether one pitcher is called tighter than another — about 65 takes, so ±6.5 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 123 pitches players chose to challenge, which are the pitches they already believed were wrong. 123 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
Alfonso Márquez
From a chain-link fence in Zacatecas to the World Series behind the plate.
Alfonso Márquez was born in Villanueva, Zacatecas, Mexico, and at age seven he left the dusty farm fields of that town. He crossed into the United States with his mother, passing through a small hole in a chain-link fence. Orange County, California, became home. He graduated from Fullerton Union High School in 1990, learned English, and eventually bought a house.
The umpiring ranks came next. He worked his first big-league game on August 13, 1999, calling home plate in a doubleheader. The assignments grew from there: World Series in 2006, 2011, and 2015, and All-Star Games in 2006 and 2018. Prior to the 2020 season, he was promoted to crew chief, becoming the first full-time Latino-born crew chief in MLB history.
Behind the Mask
During a 2011 game, Márquez ejected Toronto Blue Jays pitcher Jon Rauch after a verbal exchange. Rauch had to be restrained by teammates and coaches; his jersey was ripped off during the scuffle.
Away from the ballpark, Márquez founded a nonprofit group called Fonzie's Kids to benefit poor children.
He works behind the plate in 2026. We have graded him in 18 games this season, and the record on this page is the reason his name is here.
Reporting: Wikipedia, Los Angeles Times, Close Call Sports, Baseball Reference. 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 |
|---|---|---|---|---|
| CHC @ AZ2026-08-26 | B- | 0.2 AZ | 2/5 | If it was close, it was a strike. The hitters noticed. |
| PIT @ LAD2026-08-22 | C+ | 0.5 PIT | 2/5 | A small strike zone, generously enforced for the offense. |
| LAA @ HOU2026-08-18 | B | 0.2 HOU | 5/8 | A busy night for the machines in the truck. |
| MIL @ SD2026-08-12 | B- | 0.6 MIL | 5/9 | The players kept asking for a second opinion — and kept getting one. |
| CWS @ TB2026-08-01 | B | 1.0 TB | 5/9 | The players kept asking for a second opinion — and kept getting one. |
| CLE @ CIN2026-07-28 | B+ | 0.6 CIN | 4/8 | A workmanlike night — nothing to frame, nothing to fix. |
| AZ @ STL2026-07-23 | B- | 0.7 STL | 2/4 | Corner-to-corner and then some. |
| TB @ BOS2026-07-19 | B+ | 0.0 TB | 2/4 | Down the middle. Both dugouts had the same zone. |
| MIL @ PIT2026-07-12 | B | 0.4 MIL | 2/5 | The kind of night where the umpire is the least of the story. |
| PHI @ CIN2026-07-08 | B- | 0.7 PHI | 2/4 | Not the sharpest, and the grade agrees. |
| NYM @ ATL2026-07-04 | B- | 1.6 NYM | 0/4 | Tonight's zone had a rooting interest. |
| DET @ NYY2026-06-29 | C+ | 0.5 DET | 6/7 | The challenge cart got its steps in. |
| MIN @ TEX2026-06-16 | B+ | 0.6 TEX | 3/6 | Down the middle. Both dugouts had the same zone. |
| CIN @ SD2026-06-10 | B | 1.0 SD | 5/6 | The players kept asking for a second opinion — and kept getting one. |
| LAA @ TB2026-05-30 | B- | 0.1 TB | 2/6 | Reliable as a Tuesday: no complaints, no headlines. |
| WSH @ CLE2026-05-25 | A | 0.8 WSH | 1/2 | Solid and unspectacular — exactly what the job asks. |
| ATL @ MIA2026-05-18 | A | 0.4 ATL | 3/4 | Solid and unspectacular — exactly what the job asks. |
| ATH @ PHI2026-05-07 | B- | 0.3 PHI | 3/3 | Corner-to-corner and then some. |
| BAL @ NYY2026-05-03 | B- | 1.4 NYY | 3/5 | The grade leaned — the ledger says which way. |
| AZ @ MIL2026-04-29 | B | 0.5 MIL | 2/4 | Pitchers earned every strike the hard way. |
| ATH @ SEA2026-04-22 | C | 0.2 ATH | 3/5 | Squeezed the edges; the hitters didn't mind at all. |
| STL @ HOU2026-04-17 | B+ | 0.4 STL | 1/2 | Down the middle. Both dugouts had the same zone. |
| ATL @ AZ2026-04-04 | B | 0.5 ATL | 1/2 | Down the middle. Both dugouts had the same zone. |
| NYY @ SEA2026-03-31 | B- | 0.6 SEA | 3/5 | The zone kept to itself — the hitters said thanks. |
| DET @ SD2026-03-26 | A | 0.8 SD | 1/1 | Called a fair game and let the players decide it. |