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Norm Cash
Norm Cash (Norman Dalton Cash), American MLB first baseman 1958–1974, Chicago White Sox and Detroit Tigers; 1961 AL batting champion (.361, admitted corked bat), 377 career home runs, 1968 World Series champion, never elected to the Baseball Hall of Fame.
Northwoods League
Northwoods League: summer collegiate baseball and softball league founded 1994 in Rochester, Minnesota; 26 baseball teams in 2026 across seven U.S. states and Ontario, 72-game season, 370+ MLB alumni including Scherzer and Sale.
Oakland Athletics
Oakland Athletics, MLB franchise founded in Philadelphia in 1901 (Connie Mack), also in Kansas City and Oakland; four World Series titles in Oakland, Moneyball pioneer, relocating to a $1.75 billion Las Vegas Strip ballpark in 2028 via West Sacramento.
Oakland Ballers
Oakland Ballers, the B's, independent Pioneer League baseball team founded November 2023 by Bryan Carmel and Paul Freedman after the A's Las Vegas move; plays at Raimondi Park, fan-owned via crowdfunding, 2025 league champions.
Oakland Coliseum
Oakland-Alameda County Coliseum, opened September 1966 in East Oakland; home of the Raiders until 2019 and the Athletics 1968–2024; now hosts Oakland Roots soccer and cricket, with the site sold for redevelopment.
Octavio Dotel
Octavio Dotel (1973-2025), Dominican MLB relief pitcher who played for a record 13 teams (1999-2013), won the 2011 World Series with St. Louis, and died in the 2025 Jet Set nightclub roof collapse in Santo Domingo.
Oh Seung Hwan
Oh Seung Hwan (오승환), "The Final Boss" or "Stone Buddha," South Korean closer born 1982; KBO all-time saves leader, 2008 Olympic gold medalist, pitched for Samsung Lions, Hanshin, Cardinals, Blue Jays, and Rockies.
Oklahoma City Comets
Oklahoma City Comets, formerly the OKC Dodgers, RedHawks, and 89ers: Triple-A Pacific Coast League affiliate of the Los Angeles Dodgers since 2015, named for Mickey Mantle, the 'Commerce Comet'; plays at 9,000-seat Chickasaw Bricktown Ballpark.
Olly olly oxen free
Olly olly oxen free, also spelled Ollie ollie oxen free, is a catchphrase in children's games like hide and seek, shouted so out or hiding players can come in free.
Omaha Storm Chasers
Omaha Storm Chasers: Triple-A International League baseball team in Papillion, Nebraska, Kansas City Royals affiliate since 1969; renamed from Omaha Royals in 2011, plays at Werner Park, eight league championships including 2024 IL title.
Omar Ajete
Omar Ajete (Omar Ajete Iglesias), Cuban left-handed pitcher born 1965 in San Juan y Martínez, Pinar del Río; two Olympic baseball golds (1992, 1996) and silver (2000), 179 Serie Nacional wins with Pinar del Río.
Omar Linares
Omar Linares Izquierdo, "El Niño" Linares, Cuban third baseman (born 1967, Pinar del Río), .368 with 404 home runs in 20 National Series seasons, two Olympic golds, never played MLB.
Omar Vizquel
Omar Vizquel (Little O), Venezuelan MLB shortstop 1989-2012; holds records for games and double plays at shortstop, won 11 Gold Gloves, got 2,877 hits; Hall of Fame vote peaked at 52.6% in 2020, fell to 18.4% by 2026.
On-base percentage
On-base percentage (OBP, OBA): baseball rate statistic, (H+BB+HBP)/(AB+BB+HBP+SF). Devised by Branch Rickey and Allan Roth; AL official 1979, NL 1984; records Bonds .609 (2004), Williams .482 career.
On-base plus slugging
On-base plus slugging (OPS) is a baseball stat equal to on-base percentage plus slugging percentage, devised by Pete Palmer; league average is about .700-.750, and OPS+ normalizes it to 100 with park and league adjustments.
ONT Field
ONT Field is a 6,000-seat baseball stadium in Ontario, California, home of the Ontario Tower Buzzers, Dodgers Single-A affiliate, named under a ten-year OIAA-Legends Global naming rights deal capped at $1.2 million annually.
Ontario Tower Buzzers
Ontario Tower Buzzers: Single-A California League baseball team in Ontario, California, Los Angeles Dodgers affiliate debuting 2026 at ONT Field, aviation- and Top Gun-themed, successor to the Rancho Cucamonga Quakes franchise rights.
Oracle Park
Oracle Park (formerly Pacific Bell Park, SBC Park, AT&T Park) is the San Francisco Giants' waterfront MLB stadium, opened April 11, 2000, privately financed at $357 million, a pitcher's park with McCovey Cove splash hits and a 42,300 capacity.
Orel Hershiser
Orel Hershiser (Bulldog), born 1958, American MLB pitcher 1983-2000; 1988 unanimous NL Cy Young with record 59 scoreless innings, NLCS and World Series MVP, 1995 ALCS MVP; not in Hall of Fame; Dodgers broadcaster.
Origins of baseball
Origins of baseball: evolution of the sport from medieval English and European bat-and-ball games (stool ball, trap ball, rounders) to the 1845 Knickerbocker rules; debunks the Doubleday-Cooperstown and rounders-descent myths.
Oriole Park at Camden Yards
Oriole Park at Camden Yards, the Baltimore Orioles' MLB ballpark since April 6, 1992, built by the Maryland Stadium Authority with HOK on the B&O rail yards; the retro-design template with the B&O Warehouse, Eutaw Street, 45,971 capacity, and a 30-year lease signed in 2023.
Orix Buffaloes (オリックス・バファローズ)
Orix Buffaloes (オリックス・バファローズ), NPB Pacific League team at Kyocera Dome Osaka; formed 2005 from Orix Blue Wave–Kintetsu Buffaloes merger; 15 PL pennants, 5 Japan Series titles including 2022.
Orlando Cabrera
Orlando Luis Cabrera (born 1974, Cartagena, Colombia) is a Colombian former MLB shortstop (1997-2011), two-time Gold Glove winner, 2004 Red Sox World Series champion, 2,055 career hits, nine teams.
Orlando Cepeda
Orlando Cepeda (Peruchín, Baby Bull), Puerto Rican Hall of Fame first baseman (1937–2024); 1958 NL Rookie of the Year, unanimous 1967 NL MVP with the World Series champion Cardinals, 379 career home runs, elected 1999.
Orlando Hernández
Orlando "El Duque" Hernández (born 1965) is a Cuban former MLB pitcher who defected in 1997, won four World Series (Yankees 1998-2000, White Sox 2005), and went 90-65 with a 4.13 ERA.
Osvaldo Fernandez
Osvaldo Fernandez, born Osvaldo Fernández Rodríguez in 1966 in Holguín, Cuba, is a Cuban former pitcher who won 1992 Olympic gold and pitched in MLB.
Otto Kemp
Otto Kemp (Otto Severson Kemp, born 1999) is an American MLB infielder-outfielder for the Philadelphia Phillies; an undrafted free agent from Point Loma Nazarene University who debuted June 7, 2025.
Out (baseball)
Out (baseball): a batter or runner retired; the force out retires a runner by tagging the base he must advance to, removed when a trailing runner is forced out first, unlike tag outs and timing plays.
Ozzie Albies
Ozzie Albies (Ozhaino Jurdy Jiandro Albies), Curaçao-born Atlanta Braves second baseman, MLB debut 2017; 2021 World Series champion, 3x All-Star, 2021 30/100/100 season, career .262 with 179 home runs.
Ozzie Guillén
Ozzie Guillén (Oswaldo José Guillén), born 1964 in Ocumare del Tuy, Venezuela, is a former MLB shortstop and manager: 1985 AL Rookie of the Year with the White Sox, first Latino manager to win a World Series (2005), later Marlins manager, No. 13 retired in 2026.