NOTE: Due to a strike in mid-season, the season was divided into a first half and a second half. The division winner of the first half played the division winner of the second half.
American League Championship Series MVP: Graig Nettles
National League Championship Series MVP: Burt Hooton
January 8 - The Cincinnati Reds sign free agent first baseman Larry Biittner. The Reds become the last team to sign a free agent under the system established in 1976.
February 12 – Reputedly because the Boston Red Sox mailed out his contract two days late, catcherCarlton Fisk is declared a free agent. He will later sign with the Chicago White Sox.
February 4 - The Chicago White Sox sign free agent infielder Bill Almon
March 11 – Johnny Mize and Rube Foster are elected to the Hall of Fame by the Special Veterans Committee. Mize hit.312 with 359 home runs in 15 seasons for the Cardinals and New York Giants, while Foster was a star pitcher, manager and pioneer of the Negro Leagues during the first quarter of the 20th century.
March 18 - Carlton Fisk officially signs a contract with the Chicago White Sox
March 30 - The Philadelphia Phillies sell the contract of Greg Luzinski to the Chicago White Sox.
April–May
April 1 - The California Angels make multiple trades. The first trade they send first baseman Jason Thompson to the Pittsburgh Pirates for pitcher Mickey Mahler and catcher Ed Ott. In the second trade, the Angels send starting shortstop Dickie Thon to the Houston Astros for pitcher Ken Forsch
April 9 – After pitcher Jerry Reuss pulls a muscle, rookie Fernando Valenzuela is given his first starting assignment. His first Major League start results in a five-hit shutout. It is the beginning of what will be called "Fernandomania" in Southern California.
April 10 – Carlton Fisk debuts with the Chicago White Sox, coincidentally in Fenway Park against his former team, the Boston Red Sox. Fisk hits a three-run home run in the eighth to secure a 5-3 win for Chicago.
April 11 - Don Sutton was back in Dodger Stadium, but for the first time in 15 years, he was not pitching for the Dodgers, instead he's pitching for the Houston Astros. The Dodgers welcomed their former ace back by lighting him up for 6 runs on 8 hits in 4 innings as the Dodgers beat the Astros, 7-4.
April 18 – Tom Seaver of the Cincinnati Reds records his 3000th career strikeout. Keith Hernandez is the victim.
April 27 – Just 18 days after his first start, Fernando Valenzuela has grabbed the attention of the baseball world. In just his fifth start, he pitches his fourth complete game shutout running his record to 5-0 with a microscopic 0.20 ERA. He is also batting over.400 to help his own cause.
April 29 – Steve Carlton of the Philadelphia Phillies records his 3000th career strikeout. April 1981 is the only month in history to have two pitchers reach this milestone. He is the first left-handed pitcher in Major League history to reach that mark.
May 10 – In the second game of a doubleheader, Charlie Lea of the Montreal Expos no-hits the San Francisco Giants 4-0. The no-hitter is the first in the history of Olympic Stadium, which will witness only one other no-hitter, by Philadelphia's Tommy Greene in.
May 15 – Len Barker of the Cleveland Indians pitches a perfect game against the Toronto Blue Jays, 3-0, at Cleveland Municipal Stadium. He struck out 11, all swinging, after the third inning and never had a 3-ball count on any batter on a misty, rain-soaked night where only 7,290 fans took in the game. Current Indians broadcaster Rick Manning caught the 27th out of the night on a fly ball to center field. Barker's catcher, Ron Hassey will later catch Dennis Martínez's 1991 perfect game making him the first catcher in history to catch two perfect games.
May 21 – Ron Darling of Yale University pitches a no-hitter through eleven innings against St. John's University. In the 12th inning, St. John's broke up the no-hitter and then scored on a double-steal to beat Yale 1-0. Darling's performance remains the longest no-hitter in NCAA history and the game is considered by some to be the best in college baseball history. Frank Viola was the opposing pitcher for St. John's.
May 25 – Carl Yastrzemski plays in his 3,000th major league game, scoring the winning run in Boston's 8–7 triumph over Cleveland. Yaz joins Ty Cobb, Stan Musial and Hank Aaron as the fourth major leaguer to appear in 3,000 games.
* The Chicago Cubs select outfielder Joe Carter with their first round selection.
June 10 – Pete Rose hits a Nolan Ryan pitch in his first at-bat for the 3,630th safe hit of his career; tying Stan Musial's National League record for career hits. He would strike out in his next three at-bats in the game, however, in his bid to break the record.
June 12 – After meeting with major league owners for most of the previous day, players' union chief Marvin Miller announces, "We have accomplished nothing. The strike is on", thus beginning the longest labor action to date in baseball history. By the time the season resumes on August 10, 706 games will have been canceled.
June 16 – In the midst of the players' strike, William Wrigley III announces the sale of the Chicago Cubs to the Tribune Company for $20 million. This ends the decades-long association between the Wrigley family and the Cubs.
June 20 - Bernie Carbo signs a minor league with the Detroit Tigers. He plays in just 19 games for their Triple A team in Evansville.
June 23 – The Pawtucket Red Sox beat the Rochester Red Wings, 3-2, in the 33rd inning of the longest game in professional baseball history. This game had started 67 days earlier was halted in the early morning of April 19, with the score tied 2-2 after 32 innings and more than eight hours of game time. The game ended 18 minutes after it resumed, with Dave Koza hitting an RBI-single that brought Marty Barrett with the winning run. Future Hall of FamersWade Boggs and Cal Ripken, Jr. participated for Pawtucket and Rochester, respectively.
July 11 - The Pittsburgh Pirates sign undrafted amateur free agent Bobby Bonilla.
August–September
August 6 – As a result of the nearly two-month interruption in play because of the strike, major league owners elect to split the 1981 season into two halves, with the first-place teams from each half in each division meeting in a best-of-five divisional playoff series. The last time the major leagues played a split season was 1892. The Oakland Athletics, New York Yankees, Philadelphia Phillies and Los Angeles Dodgers suddenly find themselves guaranteed playoff spots as first-half champions.
August 9 – At Cleveland Stadium, the National League wins its tenth consecutive All-Star Game over the American League, 5-4. Gary Carter hits two home runs and is selected the MVP. The 1981 Midsummer Classic becomes the second All-Star Game ever played during the month of August, the first having taken place on August 3, 1959.
August 10 – Pete Rose singles in the 8th inning off Mark Littell of the St. Louis Cardinals to break Stan Musial's National League record for career hits.
August 24 – Kent Hrbek debuts as a Minnesota Twin. His twelfth-inning home run beats the Yankees 3-2 in New York. Hrbek will go on to have a 14-year career with his hometown team.
* The Philadelphia Phillies release John Vukovich, ending his major league career.
September 3 - The St. Louis Cardinals sell the contract of pitcher Donnie Moore to the Mailwaukee Brewers.
September 4 – In the conclusion of the longest game in Fenway Park history, the Seattle Mariners beat the Boston Red Sox 8–7 in 20 innings. The game began on September 3, but was suspended after 19 innings with the score tied 7-7.
September 6 – Despite having won the first-half American League East title, New York Yankees manager Gene Michael is replaced by Bob Lemon, who managed the club in 1978–79. The Yankees are under.500 in the second half of the season.
September 6 – The Los Angeles Dodgers' Fernando Valenzuela beats the St. Louis Cardinals 5-0 to tie the National League record of seven shutouts by a rookie pitcher.
September 26 – Nolan Ryan of the Houston Astros breaks the record of four no hitters by pitcher Sandy Koufax by pitching his fifth career no hitter in the Astrodome against, coincidentally, Koufax's former team, the Los Angeles Dodgers.
September 30 – The Kansas City Royals defeat the Minnesota Twins, 5-2, in the last Major League game to be played at Metropolitan Stadium, as the Twins prepare to move into the new Hubert H. Humphrey Metrodome. Clint Hurdle hits the last outdoor Major League home run in Minnesota until Target Field opens twenty-eight seasons later.
October–December
October 3 – Bob Horner hits two home runs and scores the winning run to give the Atlanta Braves a 4–3 win over the Cincinnati Reds, and give the Houston Astros the second-half title in the NL West division. Cincinnati, which lost the first-half title to the Dodgers by one-half game, will finish with the best overall record in the major leagues, but will miss the playoffs due to not winning either half's division title.
October 3 – The Milwaukee Brewers and Montreal Expos clinch their first postseason appearances. Milwaukee beats Detroit 2–1 to wrap up the second-half title in the AL East division, while Montréal edges the Mets 5–4 to win the NL East division's second playoff spot..
October 5 – The Kansas City Royals shut out Cleveland 9–0 in the first game of a scheduled doubleheader to clinch the second-half title in the AL West division. The second game is canceled as irrelevant. This was a make-up game after the scheduled season ended the day before.
* Mark Fidrych is released by the Detroit Tigers. Fidrych had been an all-star and rookie of the year a few seasons prior, and became a pop culture figure in baseball.
October 19 – Rick Monday of the Los Angeles Dodgers hits a ninth inning home run to break a 1-1 tie, and secure a Game five victory in the National League Championship Series. The losing Montréal Expos had been leading the series 2 games-to-one in what would be their only post season appearance.
October 21 - The New York Yankees trade outfielder Willie McGee to the St. Louis Cardinals for pitcher Bob Sykes. The trade would go on to be lopsided as McGee would become an all-star for the Cardinals, whereas Sykes would never pitcher a game on the major league level for the Yankees and would be out of organized baseball after the 1982 season.
October 26 - The Pittsburgh Pirates released Kurt Bevacqua.
October 28 – Pedro Guerrero drives in five runs, and pitcher Burt Hooton and the Los Angeles Dodgers beat the New York Yankees, 9–2, to win the 1981 World Series in six games. In a remarkable postseason, the Dodgers rallied from a 2-0 deficit against the Astros in the division series, they rallied from a 2 games to 1 deficit against the Expos in the National League Championship series, and they rallied from a 2-0 deficit against the Yankees in the World Series. Guerrero, Ron Cey and Steve Yeager are named co-MVPs.
October 28- Pitcher George Frazier of the New York Yankees makes dubious history when he is credited with the loss in game six of the world Series, making him the first pitcher with three losses in a best of seven series since Lefty Williams of the Chicago White Sox in 1919.
November 4 The Cincinnari Reds trade outfielder Ken Griffey Sr. to the New York Yankees in exchange for minor leaguer Brian Ryder and a player to be named later. On December 9th, the Yankees sent pitcher Freddie Tolliver to the Reds to complete the trade.
November 11 – Fernando Valenzuela of the Los Angeles Dodgers wins the National League Cy Young Award, becoming the first rookie to win the award.
November 20 – In a blockbuster three team trade, the Cleveland Indians send catcher Bo Díaz to the Philadelphia Phillies; the Phillies sent Lonnie Smith to the St. Louis Cardinals; the Cardinals sent pitchers Silvio Martinez and Lary Sorensen to the Indians, and the Phillies sent a player to be named later to the Indians. The Phillies sent Scott Munninghoff to the Indians on December 9 to complete the trade.
November 25 – Rollie Fingers of the Milwaukee Brewers becomes the first relief pitcher ever to win the American League MVP Award, edging Rickey Henderson of the Oakland Athletics, 319 to 308. Fingers saved 28 games while posting a significant 1.04 ERA.
December 2 – Los Angeles Dodgers pitcher Fernando Valenzuela became the third consecutive Dodgers player to be named National League Rookie of the Year. The Mexican left-hander posted a 13-7 record with a 2.48 ERA and led the NL in strikeouts, games started, complete games, shutouts and innings pitched. His 13 wins tied him with Steve Carlton in second place behind Tom Seaver, who finished with 14. Valenzuela also made his first All-Star appearance and received both the Cy Young Award and TSN Rookie of the Year.
December 6 - The Philadelphia Philles sell the contract of Bob Boone to the California Angels.
December 18 - The Cincinnati Reds trade Ray Knight to the Houston Astros in exchange for outfielder Cesar Cedeno.
January 3 – Lou Fette, 73, All-Star pitcher who posted a 41-40 record with a 3.15 ERA in 109 games for the Boston Braves and Brooklyn Dodgers, while leading the National League for the most shutouts in 1937 and 1939.
January 6 – Fred Stiely, 79, pitcher who played from 1929 through 1931 for the St. Louis Browns of the American League.
January 7 – Irv Stein, 69, pitcher for the 1932 Philadelphia Athletics of the American League.
January 17 – Owen Kahn, 75, pinch-hitter in one game for the 1930 Boston Braves.
January 26 – Ray Oyler, 42, shortstop known for his excellent glovework with the Detroit Tigers' 1968 champions, afterwards taken in the expansion draft by the Seattle Pilots.
January 27 – Huck Geary, 64, shortstop for the Pittsburgh Pirates from 1942 to 1943.
January 30 – Marino Pieretti, 60, Italian pitcher who posted a 30-38 record with a 4.53 ERA for the Washington Senators, Chicago White Sox and Cleveland Indians from 1945 to 1950.
February
February 2 – Al Van Camp, 77, first baseman/left fielder who played from 1928 to 1932 for the Cleveland Indians and Boston Red Sox.
February 4 – Grant Gillis, 70, utility infielder for the Washington Senators and Boston Red Sox between 1927 and 1929.
February 6 – Cactus Keck, 82, pitcher for the Cincinnati Reds from 1922 to 1923.
February 15 – Cotton Pippen, 69, pitcher for the St. Louis Cardinals, Philadelphia Athletics and Detroit Tigers from 1936 to 1940, better known as the pitcher that struck out Ted Williams in his first major league at-bat.
February 19 – Sam Barnes, 81, second baseman for the Detroit Tigers in the 1921 season.
February 22 – Andy High, 83, National League third baseman who hit a.284 average in 1314 games for five different teams, and a member of the St. Louis Cardinals 1931 World Series Champions.
February 23 – Myrl Brown, 86, pitcher who posted a 3-1 record in seven games for the 1922 Pittsburgh Pirates.
February 25 – Frank McCrea, 84, backup catcher for the 1925 Cleveland Indians.
March
March 6 – Wade Lefler, 84, backup outfielder who played for the Boston Braves and Washington Senators during the 1924 season.
March 7 – Pee-Wee Wanninger, 78, backup shortstop for the Yankees, Red Sox and Reds, better known as the player who replaced Everett Scott with the Yankees in to end his then major league record of 1,307 consecutive games.
March 8 – Gowell Claset, 73, pitcher for the 1933 Philadelphia Athletics of the American League.
March 10 – Bob Elson, 76, broadcaster for the Chicago White Sox from 1931 to 1970, who also worked with the Chicago Cubs and Oakland Athletics.
March 11 – Vince Gonzales, 55, Cuban-born Mexican pitcher who played with the Washington Senators in 1955.
March 17 – Paul Dean, 67, pitcher who joined his older brother Dizzy on the St. Louis Cardinals, winning 19 games in each of his first two seasons – the brothers each won two games in the 1934 World Series.
March 17 – Joe Giebel, 89, backup catcher in three games for the 1913 Philadelphia Athletics.
March 19 – Zinn Beck, 95, backup infielder who played for the St. Louis Cardinals and New York Yankees, hitting.226 in 124 games between 1913 and 1918.
March 19 – Frank Lane, 85, general manager of the White Sox, Indians, Brewers and Cardinals known for his numerous trades.
March 20 – Gee Walker, 73, All-Star outfielder who played from 1931 through 1945 for the Tigers, White Sox, Senators, Indians and Reds, collecting a career batting average of.294, 1,991 hits, 223 stolen bases, and 124 home runs.
March 25 – Red Morgan, 97, third baseman for the 1906 Boston Americans, at the time of his death the oldest living former major leaguer.
April
April 2 – Ben Rochefort, 84, first baseman who appeared in two games with the Philadelphia Athletics in 1914.
April 3 – Clayton Lambert, 64, Cincinnati Reds pitcher in the 1946 and 1947 seasons.
April 6 – Steve Mesner, 63, third baseman for the Cubs, Cardinals and Reds in parts of six seasons, who led the National League for the most assists in 1945.
April 12 – Dick Hoover, 55, relief pitcher for the 1952 Boston Braves of the National League.
April 16 – Effa Manley, 84, owner of the Negro Leagues' Newark Eagles from 1935 to 1948.
April 27 – Emerson Dickman, 66, pitcher for the Boston Red Sox between 1936 and 1941, who later became a coach at Princeton University in the 1950s.
May
May 16 – Jim Finigan, 52, two-time All-Star second baseman and third baseman who played from 1954 to 1959 for the Philadelphia/Kansas City Athletics, Detroit Tigers, San Francisco Giants and Baltimore Orioles.
May 26 – George Smith, 79, pitcher who played from 1926 to 1930 for the Detroit Tigers and Boston Red Sox.
June
July
July 1 – Dan Daniel, 91, sportswriter for The Sporting News and various New York newspapers for over 50 years; also a member of baseball's Rules Committee.
July 8 – Merl Combs, 61, shortstop for the Boston Red Sox, Washington Senators and Cleveland Indians between 1947 and 1952.
September 13 – León Kellman, 54, legendary Panamanian catcher/manager who led his teams to three championships; also a four-time Negro League All-Star, as well as the first player in Mexican baseball history to hit two grand slams in the same game.
October
October 4 – Freddie Lindstrom, 75, Hall of Fame third baseman for the New York Giants who batted.311 lifetime, twice collecting 230 hits and batting.333 in the 1924 World Series at age 18; later coach at Northwestern.
October 17 – Johnny Peacock, 71, catcher for the Boston Red Sox, Philadelphia Blue Jays/Phillies and Brooklyn Dodgers, between 1937 and 1945.
October 22 – Taffy Wright, 70, outfielder for the Washington Senators, Chicago White Sox and Philadelphia Athletics between the 1938 and 1949 seasons.
October 25 – Pete Reiser, 62, All-Star center fielder for the Brooklyn Dodgers who led the National League in batting and four other categories in 1941 and in steals twice, but whose fearless defensive style led to numerous injuries.
November
November 2 – Hugh East, 62, pitcher for the New York Giants in a span of three seasons from 1941–1943.
November 3 – Al Jurisich, 60, pitcher and member of the 1944 St. Louis Cardinals World Series Champion team.
November 10 – Ed Lagger, 69, pitcher who appeared in eight games for the 1934 Philadelphia Athletics.
November 15 – Steve Macko, 27, middle infielder and third baseman who played for the Chicago Cubs in the 1979 and 1980 seasons.
November 17 – Red Shea, 82, pitcher for the Philadelphia Athletics and New York Giants in parts of three seasons spanning 1918–1922.
November 27 – Frank Betcher, 93, backup infielder in 35 games for the 1910 St. Louis Cardinals.
December
December 10 – John F. Kieran, 89, New York sportswriter and radio and television personality who authored books on numerous subjects.
December 28 – John Bischoff, 87, catcher for the Chicago White Sox and Boston Red Sox in the 1920s, and one of the first foreign ballplayers to play in Cuban baseball.
