June 6 – The Boston Bees sign 19-year-old left-handed pitcher Warren Spahn. June 8 - Harry Craft hits a three run home run in the fifth inning of a contest against the Brooklyn Dodgers. The hit completes the cycle for Craft, who finished the game five for five as Cincinnati defeats Brooklyn 23–2. June 12 - In one of the seasons biggest trades, the Brooklyn Dodgers acquire Joe Medwick and pitcher Curt Davis, along with cash, from the St. Louis Cardinals in exchange for outfielder Ernie Koy and pitcher Carl Doyle, along with Bert Haas and Sam Nahem. The deal is one of the first made by GM Larry MacPhail to turn the Dodgers into a contending team. June 15 – In a 12–1 victory over the Pittsburgh Pirates, the New York Giants' Harry Danning hits for a cycle against that includes an inside-the-park home run. The ball became lodged behind an Eddie Grant memorial in front of the Giants' clubhouse. June 18 - Joe Medwick, recently acquired by Brooklyn from the St. Louis Cardinals, is beaned by former teammate Bob Bowman. As Medwick is carried from the field on a stretcher, an enraged Larry MacPhail demands criminal charges be brought against Bowman, as MacPhail insisted the beaning was in response to a beef between the two ball players. July July 9 – Boston Bees outfielder Max West hits a three-run home run in the first inning, as the National League defeats the American League, 4–0, in the All-Star Game at Sportsman's Park, home of the St. Louis Cardinals. July 15 - Willis Hudlin is released by the Washington Senators. One week later, he signs with the New York Giants, making the Giants the third team Hudlin would pitch for that season. August August 3 - Upset by what he viewed as a poor performance against the Boston Bees, Cincinnati Reds catcher Willard Hershberger takes his own life hours before a double header against Boston. Less than a week after being released by the Giants, Willis Hulin signs with the St. Louis Browns, thus making the Browns the fourth team Hudlin pitched for in during the 1940 season. September September 24 – Jimmie Foxx hit his career 500th home run. September 30 – The Cleveland Indians finish one-game behind the Detroit Tigers in the American League pennant race, thus disappointing Ohio baseball fans who had been rooting all season long