The following are the baseball events of the year 1984 throughout the world.
Major league baseball final standings
- March 8 – Shortstop Pee Wee Reese and catcher Rick Ferrell are elected to the Hall of Fame by the Special Veterans Committee. Reese hit .269 in 16 seasons with the Dodgers in Brooklyn and Los Angeles, while Ferrell batted .281 with 28 home runs in 18 seasons for the Browns, Red Sox and Senators.
- May 4 – Dave Kingman of the Oakland Athletics pops a ball up that never comes down. Playing the Minnesota Twins at the Metrodome, Kingman's pop fly goes through the roof of the stadium. On May 1, 2004, Kingman appears with the catcher for the Twins that day, Mickey Hatcher and watches as he fails to catch a ball dropped from the roof.
- May 8 – Hall of Famer Kirby Puckett makes his major league debut, going 4 for 5 as his Minnesota Twins shut out California, Puckett will collect 2300 more hits before retiring prematurely in 1996 due to vision problems in his left eye.
- May 8 – May 9 – The Chicago White Sox and Milwaukee Brewers face off in a game that refuses to end. Started on the 8th, the game is suspended after a 3-3 tie and seventeen innings. When the game is resumed the next day, both teams manage to score three runs in the 21st inning, and is only ended when Harold Baines slams a home run in the bottom of the 25th inning to end the 8 hour, six minute marathon; the longest game, by time, in Major League history. Tom Seaver, the last pitcher available for the White Sox, earns the win, and then goes on to start the regularly scheduled game that day, earning a second win on one day for a starting pitcher.
- May 9 – After Mets pitching allows 31 runs in the previous three games, Ron Darling, Doug Sisk and Jesse Orosco combine to hold the Atlanta Braves to just one run at Shea Stadium.
- May 11 – Dwight Gooden out duels Fernando Valenzuela as the New York Mets defeat the Los Angeles Dodgers 2-0 at Dodger Stadium. Valenzuela strikes out eight in eight innings, while Gooden strikes out eleven in a complete game.
- May 12 – In defeating the St. Louis Cardinals 2-1 at Riverfront Stadium, Mario Soto of the Cincinnati Reds has a no-hitter broken up with two out in the ninth as George Hendrick's solo home run ties the game at 1-1. It is the only hit Soto allows. The Reds win the game for Soto in the bottom of the ninth, as Brad Gulden singles in Dave Concepción, the winning run.
- May 24 – The Detroit Tigers' Jack Morris pitches a four hit complete game victory against the California Angels to improve his record to 9-1, and the team's record to 35-5, the best 40-game start in major league history.
- May 27 – As the Cincinnati Reds played the Chicago Cubs at Wrigley Field, Cubs third baseman Ron Cey hit a long foul ball down the left field line, but third base umpire Steve Rippley incorrectly ruled it a home run. Reds pitcher Mario Soto shoves Rippley during an argument over the call. After conferring, the umpires change their decision and rule it a foul ball. However, for shoving Rippley, Soto is ejected, prompting him to charge the field and attack Cubs third base coach Don Zimmer, which triggers a ten-minute bench-clearing brawl. The Reds win the game, completing a three-game sweep of the Cubs. Four days later, National League president Chub Feeney suspends Soto five games for the incident.
- June 9 – A 12–2 victory over the Cincinnati Reds coupled with an Atlanta Braves loss give the San Diego Padres their first division lead in the National League West since May 28. The Padres do not relinquish their division lead for the remainder of the season.
- June 13 – Rick Sutcliffe, George Frazier and Ron Hassey are traded by the Cleveland Indians to the Chicago Cubs, in exchange for Joe Carter, Mel Hall, Don Schulze and Darryl Banks.
- June 16 – Leading off the fifth inning, Cincinnati Reds pitcher Mario Soto throws several brushback pitches at Atlanta Braves slugger Claudell Washington, who had homered in his last at-bat. Washington tosses his bat in the direction of Soto, and tries to go out to retrieve it, but instead walks toward the mound. The chief umpire and Reds infielder Lenny Harris attempts to restrain Washington, but he is thrown to the ground. Soto uses the distraction to punch Washington. Several of Washington's teammates attempt to hold Washington to the ground. While they are doing that, Soto fires the baseball into the crowd of players, striking Braves coach Joe Pignatano. Soto is suspended three games for this incident while Washington receives a five-game suspension for shoving Harris.
- June 19 – In his first start since being acquired from the Cleveland Indians, Rick Sutcliffe pitches into the ninth inning against the Pittsburgh Pirates at Three Rivers Stadium without allowing a run. Sutcliffe is lifted in the ninth after giving up one earned run and is charged with two more unearned runs after Lee Smith replaces him on the mound. Even though, the Cubs hold on for the 4–3 victory.
- June 23 – At Wrigley Field, the Chicago Cubs and rival St. Louis Cardinals locked up in what would be a tight game. In the bottom of the ninth inning, trailing 9–8, Cubs second baseman Ryne Sandberg hit a solo-home run off reliever Bruce Sutter. The Cardinals regained the lead in the tenth inning, 11–9, but Sandberg hit another home run against Sutter in the bottom of the frame, this time with one runner on base and two outs. In a lost cause, St. Louis outfielder Willie McGee would hit for the cycle, as the Cubs went on to win the game 12–11 in the following inning and eventually won the National League East title. Sandberg earned the MVP Award this season, with this game as a key contribution.
- July 4 – Phil Niekro of the New York Yankees records his 3,000th career strikeout. He is the second to do so on the Fourth of July, after Nolan Ryan in 1980.
- July 10 – At Candlestick Park, on the 50th anniversary of Carl Hubbell's legendary five consecutive strikeouts in the 1934 All-Star Game, National League pitchers Fernando Valenzuela and Dwight Gooden combine to fan six batters in a row for a new All-Star Game record in the NL's 3–1 triumph over the American League. After Valenzuela whiffs Dave Winfield, Reggie Jackson and George Brett in the 4th inning, Gooden, the youngest All-Star ever at age 19, fans Lance Parrish, Chet Lemon and Alvin Davis in the 5th inning. Gary Carter is named the Game MVP.
- July 21 – The New York Yankees retire Roger Maris' number 9 and Elston Howard's number 32.
- July 26 – Pete Rose of the Montreal Expos tied Ty Cobb on the career singles list, No. 3,052, with a base hit in the eighth inning in a 5-4 victory over the Pittsburgh Pirates.
- September 15 – San Diego Padres outfielder Tony Gwynn collects his 200th hit of the season in a 3–2 loss to the Houston Astros.
- September 17 :
- September 18 – The Detroit Tigers clinch the American League Eastern Division, becoming the fourth team in history to hold first place from day one of the season (joining the 1923 New York Giants, the 1927 New York Yankees, and 1955 Brooklyn Dodgers).
- September 19 – Pete Rose collects his 100th hit of the season, becoming the first player in Major League history to collect that many hits in 22 consecutive seasons. It happens to be his 725th career double, which establishes a new National League record.
- September 20 – Tim Lollar's three-run home run caps a 5-4 come-from-behind win for the San Diego Padres over the San Francisco Giants, clinching the very first division title for the Padres.
- September 23 – A 4-1 win over the New York Yankees gives the Detroit Tigers 100 wins for the season, and gives Tigers' manager Sparky Anderson the honor of being the first manager in history to guide teams to 100-win seasons in both leagues.
- September 24 – On the fifteenth anniversary of the Chicago Cubs being eliminated from the 1969 pennant chase, the Cubs' Rick Sutcliffe pitches a 4-1 two-hit complete game over the Pittsburgh Pirates in Three Rivers Stadium to clinch the National League Eastern Division title for the Cubs; the first post-season appearance for the team since 1945.
- September 25 – At Shea Stadium, 40-year-old Rusty Staub of the New York Mets hits a walk-off home run off Larry Andersen to defeat the Philadelphia Phillies 6-4. Staub, who had hit 6 home runs as a 19-year-old with the Houston Colt .45s in 1963, becomes the second player, after Ty Cobb, to hit home runs before his 20th birthday and after his 40th birthday.
- September 28 – In addition to saving 29 games this season, Minnesota Twins closer Ron Davis blows his 14th save today to tie a season record. The mark was set in 1976 by future Hall-of-Famer Rollie Fingers, and subsequently tied by Bruce Sutter (1978) and Bob Stanley (1983).
- September 30 – Mike Witt of the California Angels holds on for a 1-0 win over the Texas Rangers, the 11th perfect game since 1901.
- September 30 – In the New York Yankees' final game of the season, the American League batting race is decided when Don Mattingly goes 4 for 5 to raise his average to .343, while teammate Dave Winfield finishes with a .340 average. The two teammates battle for the league lead in batting average for most of the year.
- November 6 – Willie Hernández wins the American League MVP Award, joining Rollie Fingers as the only relief pitchers in Major League Baseball history to be named MVP and Cy Young Award winners in the same season. Boston Red Sox slugger Tony Armas finishes seventh, despite winning the home run (43) and RBI (123) titles. The last player to lead in those categories and not win is Ted Williams, twice, in the 1942 and 1947 seasons.
- November 20 – Four days after his 20th birthday, New York Mets pitcher Dwight Gooden becomes the youngest player ever to win the National League Rookie of the Year Award. Gooden posts a 17-9 record with a 2.60 ERA and a major league-leading 276 strikeouts.
- November 22 – Seattle Mariners first baseman Alvin Davis easily wins the American League Rookie of the Year Award over teammate pitcher Mark Langston and Minnesota Twins outfielder Kirby Puckett.
- November 27 – The American League Gold Glove team is announced, and is made up of the same nine players as the 1983 team: Ron Guidry (P), Lance Parrish (C), Eddie Murray (1B), Lou Whitaker (2B), Buddy Bell (3B), Alan Trammell (SS), Dwight Evans (OF), Dave Winfield (OF) and Dwayne Murphy (OF).
- January 1 – Hazel Measner, 58, Canadian pitcher who played in the All-American Girls Professional Baseball League in its 1946 season.
- January 18 – Leo Kiely, 54, pitcher for the Boston Red Sox in the 1950s, who in 1957 set two PCL records with 20 wins in relief, 14 of them in consecutive games, and also became the first major leaguer to play in Japanese Baseball, for the Mainichi Orions, in 1953.
- February 10 – Johanna Hageman, 65, one of the sixty original members of the All-American Girls Professional Baseball League in 1943.
- February 26 – Joe Kuhel, 77, first baseman for the Washington Senators and Chicago White Sox known for strong defense, batted .300 three times.
- March 18 – Charley Lau, 50, renowned hitting instructor, with the White Sox since 1981, who earned fame as the Kansas City Royals batting coach (1971–78) where his star pupil was George Brett.
- March 20 – Stan Coveleski, 94, Hall of Fame pitcher who had five 20-win seasons with the Indians and Senators, and led Cleveland to the 1920 World Series championship with three victories over the Brooklyn Dodgers; spitballer led AL in ERA twice and strikeouts once.
- April 5 – Chet Kehn, 62, pitcher for the 1942 Brooklyn Dodgers, and one of many players who only appeared in the majors during World War II.
- April 6 – Glenn Wright, 83, shortstop for the Pirates, Dodgers and White Sox.
- April 10 – Karl Spooner, 52, pitcher for the Brooklyn Dodgers who never threw a pitch in the major leagues after allowing 5 runs while recording just one out during his start in Game 6 of the 1955 World Series.
- June 17 – Jim Hegan, 63, 5-time All-Star catcher for the Indians known for outstanding defense; later a Yankees coach and scout.
- July 9 – Charlie Uhlir, 71, outfielder for Chicago White Sox in 1934.
- July 24 – Jake Dunn, 74, Negro league baseball player from 1930 to 1940.
- July 31 – Beans Reardon, 86, National League umpire from 1926 to 1949 who worked in five World Series; known for his colorful arguments and continued use of the outside chest protector.
- August 14 – Lynn McGlothen, 34, All-Star pitcher who had his best years with the St. Louis Cardinals and Chicago Cubs.
- August 16 – Tommie Aaron, 45, first baseman and left fielder who played for the Braves in Milwaukee and Atlanta; Braves coach since 1978, and younger brother of Hank Aaron.
- August 23 – Charlie Robertson, 88, pitcher who spent most of his career with the Chicago White Sox; pitched a perfect game in 1923 against the Tigers in his fourth major league start; last survivor of the 1919 White Sox team.
- August 25 – Waite Hoyt, 84, Hall of Fame pitcher whose 237 victories included 20-win seasons for the Yankees in 1927-28; won six World Series games, giving up only two unearned runs in three complete games in the 1921 Series, and was a Reds broadcaster from 1942–1965.
- August 31 – Audrey Wagner, 56, All-Star outfielder in the AAGPBL who won three home run titles, a batting crown, and the 1948 Player of the Year Award.
- September 7 – Joe Cronin, 77, Hall of Fame shortstop and manager, and AL president from 1959 to 1973, who batted .301 lifetime and had eight 100-RBI seasons; managed Senators to 1933 pennant at age 26, won 1946 flag with Boston, and was Red Sox president from 1948–1959.
- October 1 – Walter Alston, 72, Hall of Fame manager who guided Dodgers teams to seven National League pennants and four World Series championships between 1954 and 1976; 2040 wins ranked behind only John McGraw in NL history upon retirement.
- October 1 – Billy Goodman, 58, All-Star infielder for the Red Sox and White Sox who won the 1950 AL batting title.
- October 13 – Ed Carroll, 77, pitcher for the 1929 Boston Red Sox.
- October 13 – George Kelly, 89, Hall of Fame first baseman who batted over .300 six straight years with the New York Giants from 1921–26; led NL in RBI twice and home runs once, later a coach and scout.
- October 15 – Red Cox, 89, pitched three games for the 1920 Detroit Tigers.
- October 19 – Del Lundgren, 85, pitched from 1924 through 1927 for the Pittsburgh Pirates and Boston Red Sox.
- October 21 – Johnny Rigney, 69, one of the Chicago White Sox top pitchers in the years prior to World War II; later the club's general manager.
- October 22 – Babe Pinelli, 89, National League umpire from 1935 to 1956, previously a Reds third baseman; he worked in six World Series, last calling balls and strikes on Don Larsen's perfect game in 1956.
- October 26 – Gus Mancuso, 78, All-Star catcher who played on five pennant winners with the Cardinals and Giants.
- November 25 – Ival Goodman, 76, All-Star right fielder for the Cincinnati Reds who led NL in triples twice.
- November 30 – Chris Pelekoudas, 66, NL umpire from 1960 to 1975 who worked in two World Series and two NLCS.
- December 7 – Howie Reed, 47, pitcher for five teams from 1958 to 1971 including the 1965 World Series Champion Los Angeles Dodgers.
- December 16 – Debs Garms, 77, outfielder and third baseman who won the 1940 NL batting title with the Pittsburgh Pirates.
- December 20 – Gonzalo Márquez, 38, Venezuelan first baseman who batted .625 in the 1972 postseason as an Oakland Athletics rookie.
- December 20 – Steve Slayton, 82, pitcher who played for the 1928 Boston Red Sox.