February 5 - Chicago Cubs outfielder Hack Wilson, who set National League marks for home runs (56) and runs batted in (191) the previous season, signs for $35,000. His RBI record is still standing today.
May 26 - The New York Yankees defeat the Philadelphia Athletics 6-2, snapping the A's seventeen-game winning streak.
June 13 - Pittsburgh Pirates outfielderAdam Comorosky makes an unassisted double play in a 6-4 loss to the New York Giants. It is his second unassisted double play of the season (May 31 against the Chicago Cubs).
June 30 - The Philadelphia Athletics purchased Waite Hoyt from the Detroit Tigers. Despite a 3-8 record with Detroit, Hoyt wins his first four starts with the A's.
August 23 - Dick Coffman holds the Philadelphia Athletics to three hits on his way to a 1-0 victory, snapping Lefty Grove's sixteen-game winning streak. It is one of only two times the A's are shut out all season (the other being the 0-0 tie with the Senators on July 6).
September 16 - The Philadelphia A's defeat the Cleveland Indians 7-5 for their 100th victory of the season.
September 18 - Lefty Grove wins his 30th game of the season, 3-1 over the Chicago White Sox.
September 27 - In a double header on the last day of the season, the St. Louis Cardinals win their 100th & 101st game of the season. The Cardinals spent eight games out of first place all season, and were never more than 1.5 games back.
October 1 - The Reigning World Champion Philadelphia A's take game one of the World Series, 6-2 over the team they defeated in the 1930 World Series, the St. Louis Cardinals.
October 2 - George Earnshaw grounds into a double play and strikes out to end two potential rallies for the Athletics. The Cards take game two of the Series, 2-0, behind Bill Hallahan's three hit performance.
October 5 - Burleigh Grimes gives up just two hits, including a two run home run by Al Simmons in the ninth, to lead the Cardinals to a 5-2 victory in game three.
October 6 - George Earnshaw two hits the Cards to even the series at two games apiece.
October 7 - Bill Hallahan wins his second start of the series, 5-1.
October 9 - Sloppy play in the fifth and seventh innings lead to five unearned runs as the A's cruise to an 8-1 victory behind Lefty Grove.
October 10 - The St. Louis Cardinals defeat the Philadelphia Athletics, 4–2, in Game seven of the 1931 World Series, earning their second World Championship title. Bill Hallahan pitches the final out for the Cards to end the series with a 0.49 ERA.
November 30 - George Gibson comes out of retirement to manage the Pittsburgh Pirates. Ten years earlier, Gibson had led the Pirates to three first-division finishes.
January 4 - Roger Connor, 73, Hall of Fame first baseman, an outstanding slugger for the New York Giants who posted a .317 career average and held major league home run record until 1921, ranking first all-time in triples and second in hits, runs and RBI and upon retirement, while leading the National League in batting, hits, HRs, RBI and doubles once each, and hitting the first grand slam in major league history.
January 14 - Hardy Richardson, 75, second baseman and outfielder who batted .300 seven times, led National League in hits and home runs with the 1886 Detroit team, and also was among to first ten players to reach 1500 hits.
February 11 - Charles Dryden, 71, sportswriter who made his name with an idiosyncratic style that emphasized personalities in the game for the many nicknames he created, including "The Peerless Leader," "The Old Roman", "Hitless Wonders".
February 13 - Dick Phelan, 76, second baseman for the Baltimore Monumentals, Buffalo Bisons St. Louis Maroons between the 1884 and 1885 seasons.
February 15 - Billy Kinloch, 56, third baseman for the 1895 St. Louis Browns.
March 17 - Tom Gunning, 69, catcher who played from 1884 through 1889 for the Boston Beaneaters and the Philadelphia Quakers/Athletics teams.
March 19 - Joe Gannon, 54, pitcher for the 1898 St. Louis Browns.
March 27 - Ernest Barnard, 56, who served as general manager of the Cleveland Indians from 1903 to 1926, and effectively ran the team following the death of owner James Dunn in 1922, while becoming the second president of the American League in following the retirement of Ban Johnson in 1927.
March 28 - Ban Johnson, 67, founder and president of the American League from 1901 to 1927, who played major role in eradicating rowdyism prevalent in the game of the 1890s, and fiercely protected authority of umpires.
April 10 - Mickey Hughes, 64, pitcher from 1888 to 1890 for the Brooklyn Bridegrooms and Philadelphia Athletics.
April 25 - August Herrmann, 71, owner of the Cincinnati Reds from 1902 to 1927, who led the sport as chairman of the National Commission from 1903 to 1920, and ensured that the World Series would be held annually.
April 28 - Mike Mattimore, 72, pitcher/outfielder for four seasons from 1887 to 1890.
April 29 - Jimmy McAleer, 66, center fielder for the Cleveland Spiders who later managed American League teams in Cleveland, St. Louis and Washington, and also was part owner of the Boston Red Sox in the 1910s.
April 29 - John Waltz, 71, manager for the Baltimore Orioles of the National League in 1892, and also an American Association executive.
October 2 - George Bradley, 79, St. Louis Brown Stockings pitcher who hurled the first no-hitter in the National's League 1876 inaugural season, also winning 45 games and leading the league with a 1.23 ERA, while setting a major league season record with 16 shutouts tied only by Grover Alexander 40 years later.
October 6 - John Kirby, 66, National League pitcher from 1884 to 1888 for the Kansas City Cowboys, St. Louis Maroons, Indianapolis Hoosiers and Cleveland Blues.
October 14 - Al Niehaus, 32, first baseman who played with the Pittsburgh Pirates and Cincinnati Reds during the 1925 season.
October 15 - Oscar Graham, 53, pitcher for the 1907 Washington Senators.
October 24 - Pete Lamer, 57, catcher for the 1902 Chicago Orphans and the 1907 Cincinnati Reds.
October 26 - Charles Comiskey, 72, Hall of Fame first baseman/manager and owner of the Chicago White Sox since the team's formation in 1901, during which time they won four American League pennants and two World Series (1906, 1917), who previously became the first manager to win four consecutive pennants, with the St. Louis Browns (1885–1888), including the 1886 World Series title. and posted the highest winning percentage (.608) among managers of at least 1200 games.
October 30 - Joe Hornung, 74, solid left fielder and speedy base runner, who played for the Buffalo Bisons, Boston Red Caps/Beaneaters, Baltimore Orioles and New York Giants in a span of 11 seasons between 1879 and 1890.
October 30 - Jim Tyng, 75, known as the first baseball player to wear a catcher's mask while playing for Harvard University (1877), who later pitched in the National League for the Boston Red Caps (1879) and the Philadelphia Phillies (1888).
November 6 - Jack Chesbro, 57, Hall of Fame pitcher; a five-time 20-games winner in 12 seasons who led both leagues in wins and winning percentage, topped the National League in shutouts twice, guided the Pittsburgh Pirates to their first pennant in 1901 and the World Series in 1902, and holds modern records with 41 wins and 48 complete games while pitching for the 1904 New York Highlanders of the American League, though he is best remembered for the wild pitch he tossed to score the Boston Red Sox pennant-clinching run on the final day of that season.
November 8 - Sam Brown, 53, catcher for the 1906/1907 Boston Beaneaters/Doves of the National League.
November 8 - Frank Meinke, 68, pitcher who played from 1884 to 1885 for the Detroit Wolverines of the National League.
November 9 - Chris Fulmer, 73, National League catcher who played with the Washington Nationals and the Baltimore Orioles in parts of three seasons spanning 1884–1889.
November 24 - Fred Lake, 65, Canadian catcher for the Boston Beaneaters, Louisville Colonels, Pittsburgh Pirates and Boston Doves in five season between 1891 and 1910, who also managed the Boston Red Sox in part of the 1909 season.
November 27 - Jack Burdock, 79, National Association second baseman for three teams from 1872–1875, and then part of the National League's inaugural year in 1876 while playing for the Hartford Dark Blues, who later played 14 more seasons for the Boston Red Stockings/Beaneaters and the Brooklyn Bridegrooms between 1877 and 1881, became the third out of the first triple play in National League history during the 1876 season, and also batted the first unassisted triple play two years later.