This list includes 67 Baseball players that start with O, from “Adam Ottavino” to “Tyler Olson”. Many are pitchers and include recent relievers alongside historical position players.
Baseball players that start with O are professional players whose last names begin with the letter O. Notable examples include Adam Ottavino, a longtime major league reliever.
Below you’ll find the table with Team, Position, and College.
Team: Shows the player’s primary or most notable MLB team, helping you connect names to franchises quickly.
Position: Lists the player’s primary field position, so you can identify role and compare players by skill set.
College: Gives the player’s college when available, useful if you follow amateur pipelines and scouting backgrounds.
Baseball players that start with O
| Name | Primary team | Position | Years (MLB) |
|---|---|---|---|
| David Ortiz | Boston Red Sox | DH | 1997–2016 |
| Mel Ott | New York Giants | RF | 1926–1947 |
| Shohei Ohtani | Los Angeles Angels | P/DH | 2018–Present |
| Paul O’Neill | New York Yankees | RF | 1985–2001 |
| John Olerud | Toronto Blue Jays | 1B | 1989–2005 |
| Matt Olson | Atlanta Braves | 1B | 2016–Present |
| Roy Oswalt | Houston Astros | P | 2001–2011 |
| Jim O’Rourke | Boston Red Caps | OF | 1876–1904 |
| Al Oliver | Pittsburgh Pirates | OF/1B | 1968–1985 |
| Buck O’Neil | Kansas City Monarchs | 1B | 1937–1955 |
| Claude Osteen | Los Angeles Dodgers | P | 1957–1975 |
| Frank O’Doul | Philadelphia Phillies | LF | 1919–1934 |
| Jesse Orosco | New York Mets | P | 1979–2003 |
| Gregg Olson (1966) | Baltimore Orioles | P | 1988–2001 |
| Bob Ojeda | New York Mets | P | 1980–1994 |
| Adam Ottavino | New York Yankees | P | 2011–Present |
| Tyler O’Neill | St. Louis Cardinals | LF | 2018–Present |
| Rougned Odor | Texas Rangers | 2B | 2014–Present |
| Darren O’Day | Baltimore Orioles | P | 2008–2022 |
| Jake Odorizzi | Tampa Bay Rays | P | 2012–Present |
| Tip O’Neill (1858) | St. Louis Browns | LF | 1883–1892 |
| José Oquendo | St. Louis Cardinals | UTL | 1983–1995 |
| Jorge Orta | Chicago White Sox | 2B | 1972–1987 |
| Ron Oester | Cincinnati Reds | 2B | 1978–1990 |
| Bob O’Farrell | St. Louis Cardinals | C | 1915–1935 |
| Hideki Okajima | Boston Red Sox | P | 2007–2011 |
| Seung-hwan Oh | St. Louis Cardinals | P | 2016–2019 |
| Pete O’Brien | Texas Rangers | 1B | 1982–1993 |
| Hank O’Day | New York Giants | P | 1884–1893 |
| Greg Olson (1960) | Atlanta Braves | C | 1989–1993 |
| Jim O’Toole | Cincinnati Reds | P | 1958–1967 |
| Joe Orsulak | Baltimore Orioles | OF | 1983–1997 |
| Johnny O’Brien (1930) | Pittsburgh Pirates | 2B/P | 1953–1958 |
| Eddie O’Brien (1930) | Pittsburgh Pirates | SS/P | 1953–1958 |
| Danny O’Connell | Milwaukee Braves | 2B | 1950–1962 |
| Troy O’Leary | Boston Red Sox | LF | 1993–2003 |
| Steve Ontiveros (1961) | Oakland Athletics | P | 1985–2000 |
| Tomo Ohka | Boston Red Sox | P | 1999–2009 |
| Joe Oeschger | Boston Braves | P | 1914–1925 |
| Bill O’Dell | Baltimore Orioles | P | 1954–1967 |
| Ryan O’Hearn | Kansas City Royals | 1B | 2018–Present |
| Dan Otero | Cleveland Indians | P | 2011–2019 |
| Alex Ochoa | New York Mets | OF | 1995–2002 |
| John O’Donoghue (1939) | Kansas City Athletics | P | 1963–1968 |
| Tom O’Malley | Baltimore Orioles | 3B | 1982–1990 |
| Miguel Ojeda | San Diego Padres | C | 2003–2006 |
| Mike Olt | Chicago Cubs | 3B | 2012–2015 |
| Reese Olson | Detroit Tigers | P | 2023–Present |
| Frank O’Rourke | Detroit Tigers | SS | 1912–1931 |
| Mike Oquist | Oakland Athletics | P | 1993–1999 |
| Ollie O’Mara | Brooklyn Robins | SS | 1912–1927 |
| Ken O’Dea | Chicago Cubs | C | 1935–1946 |
| Nate Oliver | Los Angeles Dodgers | 2B | 1963–1969 |
| Sean O’Sullivan | Los Angeles Angels | P | 2009–2016 |
| Tyler Olson | Seattle Mariners | P | 2015–2018 |
| Randy O’Neal | Detroit Tigers | P | 1984–1990 |
| John O’Rourke | Washington Nationals | OF | 1883–1893 |
| Paddy O’Connor | St. Louis Browns | C | 1908–1922 |
| John O’Donoghue (1964) | Baltimore Orioles | P | 1990–1993 |
| John O’Brien (1953) | Pittsburgh Pirates | INF | 1953–1959 |
| Chris O’Grady | Miami Marlins | P | 2017–2019 |
| Daniel Ortmeier | San Francisco Giants | OF/1B | 2008–2008 |
| Greg O’Halloran | Florida Marlins | C | 1994–1994 |
| Bill O’Hara | New York Giants | OF | 1912–1916 |
| Mike O’Berry | Boston Red Sox | C | 1979–1985 |
| Pat O’Connell | Baltimore Orioles | OF | 1994–1995 |
| Tim O’Connor | New York Mets | P | 2004–2005 |
Descriptions
David Ortiz
Big Papi is a Hall of Famer, 10-time All-Star, and three-time World Series champion. Famous for his clutch hitting, he finished his career with 541 home runs and was the 2013 World Series MVP.
Mel Ott
A Hall of Fame slugger and 12-time All-Star who spent his entire career with the Giants. He was the first National League player to surpass 500 home runs, finishing with 511.
Shohei Ohtani
A revolutionary two-way superstar, Ohtani won two unanimous AL MVP awards with the Angels. He is the only player in MLB history with 10+ home runs and 10+ pitching wins in the same season.
Paul O’Neill
A five-time All-Star and key member of four Yankees World Series championship teams. Known as “The Warrior” for his intense style of play, he won the 1994 AL batting title.
John Olerud
A two-time All-Star and two-time World Series champion known for his sweet swing and for wearing a batting helmet in the field. He won the 1993 AL batting title, hitting .363.
Matt Olson
A two-time All-Star and Gold Glove winner known for his immense power. He set the Braves’ single-season home run record with 54 in 2023, leading all of MLB in both homers and RBIs.
Roy Oswalt
A dominant right-handed pitcher and three-time All-Star for the Astros. He won the 2005 NLCS MVP award, leading Houston to its first World Series appearance, and won 20 games twice.
Jim O’Rourke
A Hall of Fame pioneer who played in four different decades. “Orator Jim” is credited with getting the first-ever hit in National League history on April 22, 1876.
Al Oliver
Scoop was a seven-time All-Star and a key member of the 1971 “Lumber Company” World Series champion Pirates. A consistent hitter, he won three Silver Slugger awards and the 1982 NL batting title.
Buck O’Neil
A Hall of Famer who was a star player and manager in the Negro Leagues, now recognized as a Major League. He later became MLB’s first Black coach and a beloved baseball ambassador.
Claude Osteen
A durable left-handed pitcher and three-time All-Star. A workhorse for the Dodgers’ rotation in the 1960s, he won 196 games over his career and pitched in two World Series.
Frank O’Doul
A two-time NL batting champion, “Lefty” O’Doul was a fantastic hitter who finished with a .349 career batting average. He later became a legendary ambassador for baseball in Japan.
Jesse Orosco
A two-time All-Star relief pitcher who holds the MLB record for most games pitched with 1,252. He recorded the final out of the 1986 World Series, famously throwing his glove in the air.
Gregg Olson (1966)
A dominant closer known for his devastating curveball. He was the 1989 AL Rookie of the Year and an All-Star, saving 160 games for the Orioles in his first five full seasons.
Bob Ojeda
A crafty left-handed pitcher who was a crucial part of the 1986 World Series champion New York Mets. He went 18-5 with a 2.57 ERA during that magical season.
Adam Ottavino
A veteran relief pitcher known for his sweeping slider. He was the first player in MLB history to be issued jersey number 0 with the Yankees, a number previously un-worn in team history.
Tyler O’Neill
A powerful outfielder known for his impressive physique and two Gold Glove awards. In 2021, he had a breakout season, hitting 34 home runs with a .912 OPS for the Cardinals.
Rougned Odor
A fiery second baseman known for his power and aggressive play. He hit over 30 home runs in three consecutive seasons for the Rangers and is remembered for his infamous punch of José Bautista.
Darren O’Day
A highly effective side-arming relief pitcher and one-time All-Star. He was a key setup man for the successful Orioles teams of the early 2010s, known for his deceptive delivery.
Jake Odorizzi
An All-Star starting pitcher who had his best years with the Rays. In his 2019 All-Star season, he posted a 15-7 record with a 3.51 ERA, showcasing his reliable mid-rotation presence.
Tip O’Neill (1858)
A 19th-century star who won two American Association batting titles. In 1887, he had one of baseball’s greatest seasons, winning the triple crown with a .435 average, 14 homers, and 123 RBIs.
José Oquendo
The Secret Weapon was a legendary utility player, famous for playing every single position on the field during his career with the Cardinals. He was also a respected and long-time coach for the organization.
Jorge Orta
A two-time All-Star second baseman, primarily with the White Sox. A versatile player from Mexico, he later became a key role player on the 1985 World Series champion Kansas City Royals.
Ron Oester
A slick-fielding second baseman who spent his entire 13-year career with his hometown Cincinnati Reds. He was a dependable part of the Reds’ infield throughout the 1980s.
Bob O’Farrell
The 1926 National League MVP, an unusual honor for a catcher of his era. A defensive specialist, he guided the Cardinals’ pitching staff to a World Series championship that season.
Hideki Okajima
A Japanese relief pitcher who made an immediate impact, becoming an All-Star in his 2007 rookie season. He was a key member of the Red Sox bullpen for their 2007 World Series championship team.
Seung-hwan Oh
A Korean relief pitcher known as “The Final Boss.” He had a dominant rookie season for the Cardinals in 2016, posting a 1.92 ERA with 103 strikeouts and 19 saves.
Pete O’Brien
A slick-fielding first baseman who was a consistent power source for the Rangers in the 1980s. He hit 20+ home runs in four different seasons and led AL first basemen in fielding percentage three times.
Hank O’Day
A pitcher in the 19th century who later became a Hall of Fame umpire. As an ump, he made the controversial “Merkle’s Boner” call in the pivotal 1908 Giants-Cubs pennant race game.
Greg Olson (1960)
An All-Star catcher for the “worst-to-first” 1991 Atlanta Braves. Known for his defensive prowess, he was a key piece of their first of many 1990s NL pennant-winning teams.
Jim O’Toole
A hard-throwing left-hander who was a mainstay in the Reds’ rotation. An All-Star in 1963, he won 19 games for the 1961 NL pennant-winning Cincinnati Reds.
Joe Orsulak
A consistent outfielder and contact hitter for several teams, most notably the Orioles. He posted a career .273 batting average over 1,463 MLB games.
Johnny O’Brien (1930)
The twin brother of Eddie, he was a second baseman and pitcher who once set a record by reaching base nine consecutive times as a pinch-hitter. He was an All-American basketball player at Seattle University.
Eddie O’Brien (1930)
An infielder and pitcher who, along with his twin brother Johnny, was a “bonus baby” for the Pirates. He played his entire career in Pittsburgh, primarily as a shortstop.
Danny O’Connell
A solid defensive infielder who was an All-Star in 1954. He was the starting second baseman for the 1957 World Series champion Milwaukee Braves.
Troy O’Leary
A steady left fielder for the Red Sox in the late 1990s. He is best remembered for hitting two home runs, including a grand slam, in a decisive 1999 ALDS game against Cleveland.
Steve Ontiveros (1961)
A journeyman pitcher who had a remarkable All-Star season in 1994 with the A’s, leading the AL with a 2.65 ERA and finishing second in WHIP.
Tomo Ohka
A Japanese starting pitcher known for his control. He won 11 games for the Montreal Expos in 2002 and was part of the Red Sox organization during their historic 2004 championship season.
Joe Oeschger
A pitcher most remembered for pitching all 26 innings of a 1-1 tie against the Brooklyn Robins on May 1, 1920. It remains the longest game by innings in MLB history.
Bill O’Dell
A two-time All-Star pitcher. He was the first player ever signed by the modern Baltimore Orioles in 1954 and became their first 20th-century pitching star.
Ryan O’Hearn
A first baseman and designated hitter known for his power from the left side. He had a memorable rookie season in 2018, hitting 12 home runs in just 44 games for the Royals.
Dan Otero
A reliable middle-relief pitcher who excelled at inducing ground balls. He was a key part of the Indians’ bullpen during their 2016 American League championship run, posting a stellar 1.53 ERA.
Alex Ochoa
A well-traveled outfielder who began his career with the Mets. He later won a championship in Japan with the Chunichi Dragons, where he was named the 2004 Japan Series MVP.
John O’Donoghue (1939)
A left-handed pitcher who was an All-Star in 1965 with the Kansas City A’s. He won 9 games and had a 3.00 ERA during that standout season.
Tom O’Malley
A versatile infielder who later became a superstar in Japan’s Nippon Professional Baseball (NPB). In Japan, he won a batting title and was the 1995 Central League MVP.
Miguel Ojeda
A catcher from Mexico who served as a backup for the Padres. He hit 8 home runs in 2005 and was a popular teammate during his time in San Diego.
Mike Olt
A former top prospect known for his power potential. He led the Chicago Cubs in home runs during the 2014 season, though he struggled to maintain a high batting average in the majors.
Reese Olson
A young starting pitcher who made his MLB debut with the Detroit Tigers in 2023. He showed promise in his rookie campaign with a high strikeout rate and solid peripheral numbers.
Frank O’Rourke
A durable infielder who played for five different teams over 18 seasons. He holds the American League record for most consecutive games played by a shortstop with 282.
Mike Oquist
A pitcher for the Orioles and A’s. He is unfortunately remembered for a 1998 start where he allowed 14 earned runs to the Yankees, one shy of the modern record.
Ollie O’Mara
A light-hitting, good-fielding shortstop in the Deadball Era, primarily for the Brooklyn Robins. He was part of two National League champion teams in 1916 and 1920.
Ken O’Dea
A backup catcher for the Cubs, Cardinals, and Braves. He was a member of three pennant-winning teams and was known for his solid defense behind the plate.
Nate Oliver
A utility infielder for the Dodgers and other clubs in the 1960s. He was a member of two World Series-winning Dodgers teams in 1963 and 1965.
Sean O’Sullivan
A journeyman starting pitcher who debuted with the Angels. He pitched for six different MLB teams over his career, embodying the role of a fringe starter and depth arm.
Tyler Olson
A left-handed relief pitcher who made his MLB debut with the Seattle Mariners. He recorded a win in his first big-league appearance.
Randy O’Neal
A right-handed pitcher who was a member of the 1984 World Series champion Detroit Tigers during his rookie season. He served as both a starter and a reliever during his career.
John O’Rourke
The younger brother of Hall of Famer Jim O’Rourke. “Honest John” was a solid outfielder and hitter, posting a career .295 batting average over ten seasons.
Paddy O’Connor
A long-tenured catcher in the Deadball Era, primarily with the Browns and Pirates. He was known more for his durability and defense than his hitting.
John O’Donoghue (1964)
A left-handed reliever and the son of former All-Star pitcher John O’Donoghue. He pitched for parts of three seasons with the Baltimore Orioles in the early 1990s.
John O’Brien (1953)
A utility infielder for several clubs in the 1950s, primarily with the Pittsburgh Pirates. He was a teammate of Roberto Clemente during Clemente’s first MLB season in 1955.
Chris O’Grady
A left-handed pitcher who appeared for the Miami Marlins as both a starter and reliever. He picked up his first career win against the eventual NL champion Los Angeles Dodgers in 2017.
Daniel Ortmeier
A tall outfielder and first baseman who played his entire MLB career with the San Francisco Giants in 2008. He spent most of his professional career in the minor leagues.
Greg O’Halloran
A catcher who played a brief four-game stint with the Florida Marlins in their second year of existence. He is one of a small group of Canadian-born catchers to play in the major leagues.
Bill O’Hara
An outfielder for the Giants and Cardinals in the 1910s. He was a member of the Giants teams that won NL pennants in 1912 and 1913.
Mike O’Berry
A backup catcher for several teams, best known for his time with the Red Sox. He was a defensive specialist who provided veteran depth behind the plate.
Pat O’Connell
An outfielder who played briefly for the Baltimore Orioles in the mid-1990s. His MLB career consisted of 14 games.
Tim O’Connor
A relief pitcher who appeared in 14 games for the New York Mets over two seasons.