Like baseball's roots reaching back to medieval Europe, the role cork has played in the development of sports is more extensive than most sports fans realize. One of the most well-known connections between cork and sports is found in baseball; its role has developed and morphed alongside America’s Game from revolutionary times, through western states being added to the Union, all the way through to today as the players of the Women’s Professional Baseball League play their inaugural season with the time-tested cork-cushioned baseball.

The earliest mentions of a bat-and-ball sport come from medieval records maintained across Europe, and it made its way to the colonies along with European settlers, with journal entries written by soldiers in the American Revolutionary War mentioning playing a game of “ball”. The exact rules and play styles of these early bat-and-ball games are frustratingly left out of the record, but we do know that by the early 19th century, two bat-and-ball games dominated recreational sports in North America: the Massachusetts Game and the New York Game - this gives a whole new context to the Yankees-Red Sox rivalry. Eventually, the rules of the New York Game won out (one imagines that, with the 100 runs required to win a Massachusetts game, today’s baseball would look very different).

The balls that were used in both the Massachusetts Game and the New York Game were highly irregular and made most often by the pitcher himself - or sometimes a local cobbler. The core of the ball was typically made of leftover rubber from shoe soles - or, regionally, fish eyes providing a bouncy and lively ball (which one imagines did not smell pleasant in the summer heat); this inner core was then wrapped in a wool or leather case and stitched together. Over the course of the game, these relatively spherical shapes became misshapen, often becoming oblong. The balls were as unregulated and creative as the rules of baseball were at the time, differing pitcher to pitcher and city to city.

In 1846, standardization of baseball began with the New York Knickerbocker Base Ball Club introducing the scorecards and inning format that we see at ballparks today, though major differences remained, such as pitching style and non-uniform balls. Regulations for the baseballs themselves were the next thing to be added, with New York’s amateur baseball clubs adopting size and weight regulations in the 1850s. These balls were heavier than the average baseball used nationwide, making them less lively, and the scores of games started to look less like modern-day basketball and more like modern football. In 1865, 91 amateur teams convened and put to paper the rules of baseball nationally, a unifying moment at the close of the American Civil War. The first professional baseball game followed in 1869, with the professional Cincinnati Red Stockings beating the amateur Great Western Baseball Club 45-9.

It wasn’t until 1876 that the National League adopted the first standardized, commercial baseball made by the Spalding company. These balls were styled on retired pitcher and company founder A.G. Spalding’s handmade ball. These balls maintained the rubber core and had the modern weight and dimensional specifications still used today. The 19th-century rubber-cored Spalding baseballs softened and broke down as each game progressed, leading to the lower run and home run averages that defined the original dead-ball era of baseball.

The cork era smashed onto the scene of baseball in 1910 when the cork-cored baseball was used in play for the first time in a Major League game. Throughout the 19th and early 20th centuries, a single baseball, when adjusted for inflation, would cost $45 - in fact bats were less expensive at the time than balls. This high cost encouraged teams to play with a single baseball for an entire game. The new cork-cored ball didn’t break down and misshape over the course of a game as the rubber-cored ball was prone to, and it produced livelier play. Its first year on the mound saw a noted increase in runs and home runs, which moderated in the following years - until a new player came onto the field. Babe Ruth’s first season in 1914 signaled the start of the big-hitters era in baseball; home runs exploded, as did the average number of runs scored in a game. In 1931, the American League adopted a cork-cushioned baseball, blending the benefits of cork and rubber to create the direct predecessor of the modern-day baseball.

“Next to religion, baseball has had a greater impact on our American way of life than any other American institution.”

— Herbert Hoover

The modern-day baseball was introduced in 1934 when the American and National Leagues agreed to adopt a single ball design (previously, each league had played with its own ball specifications). This is still the design of the baseball today and features a cork core wrapped in two layers of rubber cushioning, surrounded by wool yarn and encased in leather, stitched with exactly 108 double stitches.

When the All-American Girls Professional Baseball League launched in 1943, materials were difficult to come by, with rubber and cork rationed and diverted to the war effort. The ball that these women played with bore little resemblance to the modern baseball, and looked more like a softball with its plastic core and larger diameter. This ball didn’t last; however, a smaller cork-centered ball was adopted after the war in 1949 and was used for the remaining seasons. In 2026, women’s professional baseball returns, with the Women’s Professional Baseball League (WPBL) adopting the cork-cushioned ball, ensuring that the telltale “pop” we are all familiar with rings out on the field, albeit from aluminum bats.

The introduction of cork changed the trajectory of baseball, and the material is now quite literally wound into the fabric of the sport. The cork-cored baseball has persisted for more than 100 years, with new leagues continuing to adopt it for the superior play it provides. Cork transformed the ball at the center of America’s pastime; where might we see it transform sports next? Learn more about cork infill and its potential to revolutionize synthetic turf.

Further Reading on The Development of America’s Game