Walter Johnson retires 28 consecutive batters during a 12-inning scoreless tie against Jack Quinn and the New York Yankees. Future football immortal George Halas, batting leadoff for New York, goes 0-for-5 with two strikeouts.
August 14 – Babe Ruth hits his 17th home run, the first of seven homers in 12 days, which will include his fourth grand slam, setting an AL record until 1959.
August 24 – Cleveland Indians pitcherRay Caldwell is hit by lightning during the ninth inning of his début for the tribe. He quickly recovered, reportedly saying "Give me that danged ball and turn me toward the plate," before pitching the final out of the game.
September 2 – The National Commission recommends a best-of-nine world series, abandoning the traditional seven game series. However the change was reverted three years later and the seven game format has remained ever since.
September 10 – Ray Caldwell, the pitcher hit by lightning just a couple of weeks before, throws a no hitter in the Cleveland Indians 3–0 victory over his former team, the New York Yankees.
September 21 – In a period of rapidly played games, the Cubs beat the Braves 3–0 in 58 minutes of playing time. It takes the Robins 55 minutes to beat the Reds 3–1, with Slim Sallee throwing 65 pitches, managing to top Christy Mathewson's 69-pitch complete game.
The Brooklyn Robins defeat the Phillies twice on Fred Luderus Day in Philadelphia. The second game is the 525th in a row played by the Phillies first baseman, who is presented with a diamond stickpin and gold watch between the games to commemorate his endurance effort. He will end the season with a consecutive-game streak of 553.
Boston Red Sox pitcher Waite Hoyt throws nine perfect innings against the New York Yankees, but they score in the 13th in which he gives up 5 hits, ruining his perfect game, and losing the game 2–1.
September 27 – Babe Ruth hit his 29th home run and his first of the year in Washington, to become the first player to hit at least one home run in every AL park in the same season.