April 11 – At the Polo Grounds, Babe Ruth of the Boston Red Sox pitches a three-hitter in shutting down the New York Yankees on Opening Day, 1–0. Ruth's performance marks the start of good things to come. He will win 24 games this year, while leading the American League with 35 complete games.
May 2 – In one of the most outstanding pitching duel's in baseball history, Cincinnati Reds pitcher Fred Toney tosses a 10-inning no-hitter in a 1–0 win over the Chicago Cubs. Opposing pitcher Hippo Vaughn did not surrender a hit until a one-out single in the 10th inning.
May 7 – Babe Ruth pitches a shutout and drives in the game's only run on a sacrifice fly as the Red Sox top Walter Johnson and the Senators, 1–0.
June 23 – Ernie Shore of the Boston Red Sox pitched the most notable game of his career leading his team to a 4–0 win against the Washington Senators. Babe Ruth started the game for Boston but walked the leadoff hitter, Ray Morgan. Ruth then engaged in a heated argument with home plate umpire, Brick Owens, who tossed Ruth out of the game. Then Shore came into the game to relieve Ruth. Morgan was caught stealing, and Shore retired the next 26 Senators he faced. At the time, Shore was credited with a perfect game, but since then, the criteria have been revised, and Shore's name has been removed from the record books, although he still gets credit for a combined no-hitter.
July 6 – The Chicago White Sox put a stop to Ty Cobb's consecutive-game hitting streak, halting it at 35.
July 15 – Boston Braves catcher Hank Gowdy reports for duty with the Ohio National Guard becoming the first Major League player to enlist for service during World War I.
August 28 – The Indians' pennant chances suffer a severe blow when outfielder Tris Speaker is suspended after an argument with an umpire.
January 3 – Rynie Wolters, 74, Dutch pitcher and outfielder who hit .318 and posted a 19–23 record with the New York Mutuals, Cleveland Forest Citys and Elizabeth Resolutes between 1871 and 1873.
January 10 – Jack McFetridge, 47, pitcher who played in 1890 and 1903 with the Philadelphia Phillies of the National League.
January 13 – Jim Garry, 47, pitcher for the 1893 Boston Beaneaters.
January 16 – Charlie Geggus, 54, pitcher who posted a 10–9 record and a 2.54 ERA for the 1884 Washington Nationals of the Union Association.
January 17 – Pat McCauley, 46, backup catcher who played between 1893 and 1903 for the St. Louis Browns, Washington Senators and New York Highlanders.
January 19 – Charlie Enwright, 29, shortstop who played for the 1909 St. Louis Cardinals.
January 26 – Jim McGuire, 41, shortstop for the 1901 Cleveland Blues of the American League.
January 30 – Cyclone Ryan, 51, Irish pitcher and first baseman who played for the 1887 New York Metropolitans and the 1891 Boston Beaneaters.
January 31 – Pete O'Brien, 39, second baseman for the Cincinnati Reds, St. Louis Browns, Cleveland Naps and Washington Senators between 1901 and 1907.
February 7 – Tim Murnane, 64, first baseman and center fielder in the early years of professional baseball who became president of the New England League and went on to a distinguished tenure as sports editor of The Boston Globe for over 30 years, serving as one of the sport's leading advocates.
February 18 – Charlie Fisher, 64, third baseman who played for the Kansas City Cowboys and the Chicago Browns of the Union Association in the 1884 season.
February 18 – William Kerr, 69, co-owner of the Pittsburgh Pirates (1893–1900).
February 23 – Art Weaver, 37, catcher and infielder who played with the Cardinals, Pirates, Browns and White Sox between 1902 and 1908.
February 28 – Parson Nicholson, 53, second baseman who played for the Detroit Wolverines, Toledo Maumees and Washington Senators between 1888 and 1895.
March 4 – Joe Dowie, 51, backup outfielder for the 1889 Baltimore Orioles of the National League.
March 9 – Cooney Snyder, 45, Canadian catcher who played for the 1898 Louisville Colonels.
March 15 – John Munce, 69, outfielder for the 1884 Wilmington Quicksteps of the Union Association.
March 27 – Willie Jensen, 27, American League pitcher who played for the 1912 Detroit Tigers and the 1914 Philadelphia Athletics.
April–June
April 5 – Frank McLaughlin, 60, utility infielder and outfielder who played from 1882 through 1884 for five teams in three different leagues.
April 9 – Charlie Gould, 69, first baseman for the original Cincinnati Red Stockings of 1869 and 1870, the first team consisting entirely of professional players.
May 19 – Pat McManus, 54, who pitched for the Indianapolis Hoosiers (1889) and Philadelphia Phillies (1894) of the National League.
May 25 – Willie Sudhoff, 42, pitcher for six different teams from 1897 to 1906, who became the first to play for all St. Louis clubs both in the National and American leagues.
May 27 – Tom Ford, 50, American Association pitcher and shortstop for the Columbus Solons and the Brooklyn Gladiators during the 1890 season.
June 10 – Jack Fanning, 54, pitcher for the 1889 Indianapolis Hoosiers and 1894 Philadelphia Phillies.
July–September
July 1 – Al Buckenberger, 56, manager for four teams between 1889 and 1904, mainly for the Pittsburgh Pirates and the Boston Beaneaters of the National League.
July 1 – Henry Mathewson, 30, pitcher for the National League New York Giants in the 1906 and 1907 seasons.
July 16 – Dick Butler, 47, backup catcher for the 1897 Louisville Colonels and the 1899 Washington Senators.
July 27 – John Schappert, [?], who pitched for the St. Louis Brown Stockings of the American Association in the 1882 season.
July 28 – Whitey Ritterson, 62, catcher for the 1876 Philadelphia Athletics.
August 7 – Bill Loughran, 55, catcher for the 1884 New York Gothams of the National League.
August 24 – Al McCauley, 54, first baseman and pitcher for the Indianapolis Hoosiers, Philadelphia Phillies and Washington Statesmen between the 1884 and 1891 seasons.
August 27 – Cy Alberts, 35, pitcher for the 1910 St. Louis Cardinals.
September 13 – Gene Derby, 57, catcher for the 1885 Baltimore Orioles of the American Association.
October–December
October 12 – Bill Clay, 42, backup outfielder for the 1902 Philadelphia Phillies.
November 1 – Steve Brady, 66, outfielder who played between 1874 and 1886 for the Hartford Dark Blues, Washington Nationals and New York Metropolitans.
November 19 – King Bailey, 47, pitcher for the 1895 Cincinnati Reds.
December 2 – Mike Hooper, 67, National Association outfielder for the Baltimore Marylands between 1868 and 1873, who led his team in runs scored from 1868 to 1870.
December 17 – Frank Burlingame, 64, National League and Union Association umpire
December 20 – Will Calihan, 48, American Association pitcher who played from 1890 to 1891 with the Rochester Broncos and Philadelphia Athletics.
