» February 18, 1909: National League president Harry Pulliam, in ill health, is granted a leave of absence. The league secretary, John Heydler, assumes his duties. The NL abolishes Ladies Days, and sets a 25-player limit from May 15 to August 20. » April 23, 1909: In the 6th inning of the Reds-Pirates game in Pittsburgh, Honus Wagner steps across the plate to the other batter's box as Reds P Harry Gaspar delivers the ball. Umpire Bill Klem refuses to call him out. The Pirates win 2-1, but Reds manager Clark Griffith protests and acting NL president John Heydler backs Klem. But the league will override Heydler and Klem and order the game replayed September 20th. The Pirates will win again, by a score of 4-3.
» May 16, 1909: NL President John Heydler calls a meeting with the league's umpires to discuss ways that the new two-umpire system can prevent fighting by the players. A serious incident occurred several days earlier in Boston when Reds catcher Frank Roth attacked umpire Steve Cusack after a play at home. Several other Reds players threatened the umpire with baseball bats.
» August 2, 1909: Harry Pulliam is buried in Louisville. For the first time in history, both NL and AL games are postponed in tribute. After the funeral, a special meeting of the Board of Directors appoints John Heydler to succeed Pulliam.
» September 14, 1909: John Heydler announces that the NL will use two umpires per game in 1910.
» December 9, 1913: John K. Tener, one-time pitcher and congressman, now governor of Pennsylvania, is elected National League president for four years. John Heydler is elected secretary.
» March 5, 1916: The NL meeting of February 1916 announced that it had come to the league's attention that "some of the diamonds" didn't measure properly. On this day, John Heydler's office circulates to clubs the news of the Chicago Cubs pitching distance, and orders an engineer's certification.
» December 10, 1918: National League secretary John Heydler is formally elected president of the league. He had been acting president since John Tener stepped down last August.
» February 5, 1919: Charges brought in 1918 by Reds owner Garry Herrmann and manager Christy Mathewson against Hal Chase for betting against his team and throwing games in collusion with gamblers are dismissed by National League president John Heydler. Heydler decides Chase's sometimes indifferent play was due to "carelessness." Two weeks later John McGraw trades 1B Walter Holke and C Bill Rariden to the Reds for Chase, but the Giants will also have their problems with him. In September, McGraw will send Chase and Heinie Zimmerman home without explanation; during the investigation of the Black Sox scandal in 1920, McGraw will testify that the dismissal was because both players had thrown games and tried to enlist Fred Toney and Benny Kauff in their scheme.
» November 8, 1920: At a meeting to depose Ban Johnson, a new 12-team National League, made up of the dissenting 11 teams plus one of the five teams loyal to Johnson, is agreed to. John Heydler will be its president and Judge Landis the proposed chairman of the new commission. With no stomach for another war, four of the five American League clubs still backing Johnson agree to a joint meeting November 12th in Chicago.
» January 31, 1927: National League President John Heydler rules that Rogers Hornsby cannot continue to hold stock in the Cardinals and play for the Giants. Seemingly oblivious, the Cards board of directors meeting in St. Louis, voted stockholders a 10% dividend, earning Hornsby $2916 for his 1167 shares.
» December 11, 1928: At the National League meeting, President John Heydler proposes the designated hitter for pitchers to improve and speed up the game. He contends fans are tired of seeing weak-hitting pitchers come to bat. Heydler refers to his idea as "the tenth regular."
» December 17, 1928:
National League President John Heydler's designated hitter idea gets the backing of John McGraw, but the American League is against it.