Michael Ryan DiMuro (born October 12, 1967) is a former umpire in Major League Baseball. In 1997, DiMuro briefly became the first American umpire to work in Japanese baseball. On May 29, 2010, DiMuro was the home plate umpire for Roy Halladay's perfect game, the 20th perfect game recorded in MLB history.

Mike began his career in the Arizona League in 1991, a year out of college. He moved up to the California League (1992), Texas League (1993-1994), American Association (1995) and Pacific Coast League (1996).

In 1997, Mike umpired in the Japanese Central League in an experiment designed to introduce American umpiring standards to Nippon Professional Baseball. However, he was stunned by the casual acceptance of abuse toward umpires; after he ejected Chunichi Dragons hitter Yasuaki Taiho from a game for arguing balls and strikes, players and the team's manager swarmed him in protest and Taiho shoved him in the chest.

Other than the ejection, there were no penalties assessed to Taiho, and after consulting with officials of both the Central League and the American League, Mike resigned and returned to the United States.

Mike worked in the PCL for the remainder of 1997, although he did work his first few major league games in the AL that summer. He remained in the PCL in 1998 but came to the majors to stay in 1999, helped by the Richie Phillips-led mass resignation of MLB umpires. DiMuro wore number 16, just as his father had. He worked the 2005 All-Star Game, as well as Division Series in 2000 and 2010.

DiMuro was involved in an embarrassing play in a game between the Cleveland Indians and New York Yankees at New Yankee Stadium on June 26, 2012. With two outs in the 7th inning, the Indians' Jack Hannahan hit a pop-up towards the left field stands; Yankees LF Dewayne Wise dove into the crowd, and then came up pretending he had made the catch, running back towards his dugout and high-fiving teammate Derek Jeter along the way.

Lou never asked to see the ball, as proper protocol dictates, and indeed, it was still in the stands, as Wise had never made the catch. However, the call was left to stand, much to Hannahan's dismay, and DiMuro ejected him when he went back to take his position and argued with the umpire after seeing a replay in the clubhouse. After the game, Lou admitted his mistake:

"I went out on the ball and saw the ball into [Wise's] glove in the stands. He disappeared into the stands, and I believed that the ball was in his glove. In hindsight, I should have asked him to show me the ball, since he fell into the stands and out of my line of vision."

Mike co-founded an organization called "Blue For Kids" with fellow umpire Marvin Hudson in 2004. The organization is now called UMPS CARE Charities and is the official charity for Major League Umpires.

Mike's father Lou was an American League umpire from 1963 until 1982, when he died of injuries sustained from being hit by a car. His father also wore number 16 during his major league career. Mike's twin brother Ray also worked occasional games as a substitute umpire in the AL from 1996 to 1999. DiMuro retired on July 18, 2019, after a 20-year career.

(excerpted from Centerfield Maz, BR Bullpen & Wikipedia)