February 27 – The New York Highlanders acquire catcher Branch Rickey from the St. Louis Browns in exchange for infielder Joe Yeager. As a condition, Rickey specifies that he will not play on Sundays. Fritz Buelow replaces him on the Browns as their new catcher.
*On Opening Day, New York Giants catcher Roger Bresnahan wears shin guardsfor the first time in a major league game. The leg guards, usually used in cricket, come in handy, protecting Bresnahan from a fifth-inning foul tip. Other catchers will soon follow Bresnahan's lead and wear similar shin guards.
June 28 – The last-place Washington Senators steal a record 13 bases off catcher Branch Rickey in a 16–5 victory over New York Highlanders. Rickey, acquired last February from the St. Louis Browns, is pressed into service despite a bad shoulder because of an injury to starting pitcher Red Kleinow. Rickey's first throw to second base ends up in right field and the subsequent tosses are not much better. He almost nips Jim Delahanty on a steal of third base. In his eight innings, relief pitcher Lew Brockett helps Washington with a deliberate windup. Only pitcher Long Tom Hughes and second baseman Nig Perrine are steal-less, while Hal Chase swipes one for New York.
August 2 – Walter Johnson made his major league debut with the Washington Senators and lost to the Detroit Tigers, 3–2. The first hit Johson yielded was a bunt single by Ty Cobb.
August 11 – In the second game of a doubleheader, shortened by agreement, Ed Karger of the St. Louis Cardinals pitched a seven-inning perfect game, beating the Boston Doves, 4–0.
September 20 – One week after recording a shutout in his major league debut, Pittsburgh Pirates pitcher Nick Maddox hurled a no-hitter against the Brooklyn Superbas in a 2–1 Pirates win. At the age of 20 years and ten months, Maddox becomes the youngest pitcher to throw a no-hitter in major league history.
September 25 – Honus Wagner steals four bases, including second base, third base and home plate in the second inning against the New York Giants. Not to be outdone, his teammate Fred Clarke also swipes four bases for the only time in his career.
October 12 – In Game 5 of the World Series the Chicago Cubs would win their first World Championship by defeating the Detroit Tigers, 2–0. The Cubs would take the final four games of the series after Game 1 was declared a tie due to darkness with the score knotted at 3–3 in the 12th inning.
March 12 – Pat Hynes, 23, outfielder for the St. Louis Browns/Cardinals from 1903 to 1904
March 28 – Chick Stahl, 34, outfielder for Boston teams in the NL and AL, and manager of the Red Sox since August, who batted.305 lifetime; had three triples in 1903 World Series, and led AL in triples in 1904
June 20 – Ezra Sutton, 56, third baseman for Boston who led the National League in hits in 1884, was fifth player to collect 1000 hits, and batted.300 three times in the National Association and four times in the National League
November 26 – Eddie Burke, 41, outfielder for the Phillies/Alleghenys/Brewers/Giants from 1890 to 1895, who topped the National League in games played and times hit by pitches in 1893
