Baseball has made several changes to the ball over the game's history. Before 1876 baseballs were not uniform. Pitchers made the balls used in games, and no two were alike. In 1876 the National League was founded, and a pitcher named A.G. Spalding convinced the league to use his design with a rubber core as the model. It was the beginning of a partnership that would last for a century and create the company called Spalding Sports goods that still exists today.

During the 1910 World Series, the league approved modifying the game ball to use a center core made of cork. Home runs and runs scored per game increased during the next three years. However, pitchers adapted and began scuffing the baseball, bringing scoring back down.

In 1920, the yarn used in baseballs was replaced with higher-quality wool imported from Australia. Machine winders also began to be used. Stronger yarn and tighter winding resulted in the Live-Ball Era, and complaints about the new "rabbit ball" started. The home run rate tripled from a decade earlier, and scoring increased over a run a game.

The leagues attempted to deaden the ball with another modification in 1931. The cork center was replaced by a combination of cork and ground rubber. The changes lowered the home run rate and dropped scoring to just under five runs per game.

In December of 1937, the National League chose to further "deaden" the ball, and the American League kept their ball unchanged. In March 1938, Washington Senators owner Clark Griffith with the Bureau of Standards to test the performance of the two league's baseballs.

The resulting report stated, "no difference of any practical significance. Some National League balls are more lively than some American League balls, and some are less lively."

During World War II, rubber was needed for the war effort as the fighting impacted the supply chain. In 1943, major league baseball removed rubber from baseballs and replaced it with latex made from the dry sap from the Balata tropical tree. League commissioners claimed no differences between the new Balata balls and baseballs using rubber.

The players and team owners quickly found this was far from the truth. The use of the balata balls led to a significant drop in scoring. The ball was changed many times during the 1943 season until scoring went up to an acceptable level. In 1944, needs from the war effort spurred the development of synthetic rubber, which replaced the poorly performing balata from baseballs.

Over the next thirty-two years, only a few changes were made to the ball and appeared not to make any differences to home run rates or scoring. In 1958 balls were made an eighth of an inch thicker and an eighth of an ounce heavier. In 1974 covering of the baseball changed from horsehide to cowhide due to a horsehide shortage. In 1976 baseball ended its partnership with Spalding at the end of the season over a proposed increase of ten cents per ball over two years or a five percent increase in the contract. MLB selected Rawlings as the new supplier for the 1977 season.

In the late nineties and early 2000s, complaints of a juiced ball began again. It turned out that it wasn't the baseballs but some of the juiced players during the "Steroid Era" of baseball. In 2000, 5,963 home runs were hit, which was a record for home runs in a season. With drug testing in place for players, attention went back to the baseball's construction.

Research by Rob Arthur found evidence of changes in the composition of the baseball core. Writers Ben Lindbergh and Mitchel Lichtman obtained and tested several baseballs and found that balls produced in 2015 were slightly bouncier and balls made in 2016 were somewhat smaller with lower seams. Balls produced after 2015 were different than those made before.

On June 5, 2018, Major League Baseball purchased Rawlings, the company producing the game's baseballs since 1977. MLB paid $395 million for the manufacturer, stating it wanted more control over baseball production. Since the purchase, baseball commissioner Rob Manfred admitted that baseballs used during the 2019 season had less drag, enabling them to travel farther.

Last year MLB used two different types of balls during the season. This year, the league admitted increasing drag to deaden the ball so it won't fly as far. Expect the tinkering to continue as baseball tries to find the sweet spot for home runs and runs scored per game.