April 18 - New York Parks commissioner Robert Moses proposes a new 78-acre tract in Flushing Meadows as a site for a new National League Stadium. The plan, submitted to mayor Robert Wagner, includes a 50,000-seat stadium with a plastic dome to be built by the Parks Department.
April 21 - The Cincinnati Redlegs are involved in a bizarre play in a game against the host Milwaukee Braves. With Don Hoak on second and Gus Bell on first, Wally Post hits a ground ball to Milwaukee shortstop Johnny Logan. Hoak breaks up a potential double play by fielding the ball himself and flipping it to Logan. Hoak is called out for interference, but Post is given a single on the play. The day before, Johnny Temple let Bell’s ground ball hit him with the same result, Temple being called out for interference and Bell being awarded a single. The two incidents prompt league presidents Warren Giles and Will Harridge to jointly announce a rule change that declared both the runner and batter out if the runner intentionally interfered with a batted ball, with no runners allowed to advance.
April 22 - John Irvin Kennedy becomes the first black player in Philadelphia Phillies history, entering the game in the top of the 8th inning as a pinch runner for Solly Hemus.
April 24 - The New York Board Of Estimates fails to act on the Moses plan as outlined by Mayor Wagner.
May 7 - Cleveland Indian pitcher Herb Score is hit in the face by a line drive by New York YankeeGil McDougald, the ball breaking numerous bones in Score's face and leaving him quite bloodied. McDougald vows to quit if Score is blinded as a result. Score regains his 20/20 vision, but will miss the remainder of the 1957 season.
May 10 - Mayor George Christopher of San Francisco confers with Horace Stoneham on a possible shift of the New York Giants franchise to the West Coast.
May 28 - The National League approves the proposed moves of the Brooklyn Dodgers and The Giants to the West Coast, provided both clubs make their request before October 1 and move at the same time.
May 29 - New York mayor Robert Wagner says he plans to confer with the Giants and Dodgers about the proposed move, but that the city will not be "blackjacked" into anything.
May 30 - Walter O'Malley rejects a Queens group's offer to buy the Dodgers.
July-September[]
July 18 - Horace Stoneham says the Giants will quit New York after the season. He says he has not heard anything more from San Francisco and that his move is not contingent on that of the Dodgers. He sees a new stadium or joint occupancy with the New York Yankees as the only reason for the Giants to stay in New York.
August 19 - As Horace Stoneham cites poor attendance as the reason for The Giants' move, The Giants board of directors votes 8-1 to move to California in 1958, as San Francisco promises a new stadium in the Bayview area. The only dissenting vote is by M. Donald Grant.
September 29 - With 1895 Giants manager Jack Doyle among the 11,606 looking on, the Giants lose their last game at the Polo Grounds 9-1 to the Pittsburgh Pirates. Pirate Pitcher Bob Friend defeats Johnny Antonelli.
October-December[]
October 7 - the Los Angeles City Council approves the Chavez Ravine site for Dodger Stadium by a vote of 10 to 4. It would not be until 1962 that a New York team will again represent the National League.
October 8 - Walter O'Malley announces that the Dodgers will be moving to Los Angeles for the 1958 season.
April 15 - Jack Coombs, 74, pitcher with 158 career victories including a 31-9 campaign for the 1910 Athletics; pitched a complete 24-inning game on September 1, 1906, winning 4-1; later the baseball coach at Duke University from 1929 to 1952
July 3 - Dolf Luque, 66, Cuban pitcher who won 194 games in the National League
