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Baseball Ball – Evolution of the Iconic Sphere

  • Historical review of how baseball’s size, weight, and materials have changed over the years
  • Explore how the ball specification changes impacted baseball games

The ball used in baseball has undergone substantial changes since its initial conception. From rough and ready, homemade versions to the sophisticated, precision-engineered balls we see in modern-day Major League Baseball (MLB), each iteration has contributed to shaping the sport as we know it today.

Despite its uncomplicated appearance, the baseball is in fact a precision-made object.

Today, Rawlings (founded in 1887) has had an exclusive contract to supply the major leagues with baseballs since 1977. The majority of Rawlings baseballs are made in the Costa Rica plant which makes about 900,000 baseballs a year (Rawlings China plants make 2 million + baseballs per year and the average baseball remains in play for only five to seven pitches in a Major League game!).

Overall Rawlings supplies about 1.8 million of them to the major and minor league teams.  The remaining baseballs are sold to the public.

Table of Contents

Anatomy of a Baseball

Picture below is a brand new, dissected Minor League Baseball from my own collection.

I have this weird attachment to baseballs where I can’t seem to get rid of any baseballs, including the ones with busted seams and broken stitches. But for my readers, I held back my tears and cut into one so that you can see the innards of an actual base ball.

Anatomy of a Modern MiLB Baseball

The materials uses inside and outside the ball will vary, depending on the level of play and the league you play in. Excluding safety baseballs, all recreation and tournament grade baseballs will have similar combination of these components that are found in MLB and MiLB baseballs:

Current Standard

The current standard for a baseball is 9 to 9.25 inches in circumference, and between 5 and 5.25 ounces (around 142 to 149 grams) in weight.

This specification is according to the regulations defined by Major League Baseball (MLB). This weight standard has been in place for over a century, illustrating its integral role in shaping the game we know and love today.

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Changes in Size, Weight, and Materials used in Making Baseballs

Throughout history, changes in the size, weight, and materials used to construct baseballs have had a profound impact on the game.

As per the latest MLB Rule 3.01 (2021), an official league baseball has a circumference of 9 to 9.25 inches (22.86 to 23.495 cm) and weighs about 5 ounces (141.75 grams). It’s made up of a cork and rubber core, surrounded by layers of wool and cotton yarn, covered with cowhide, and held together by red stitches.


This section explores the fascinating journey of how baseballs have evolved, from the early days of handmade spheres to the standardized, technologically advanced balls of today.

Early Baseballs (1800s)

In the early years of baseball, the balls were often handmade. Often, individuals used what they had on hand to create these balls. A core made from scrap rubber materials was wrapped in yarn or string and then covered in horsehide leather.

Lemon Peel Baseball (circa 1830)

These baseballs lacked uniformity; their size, weight, and bounce varied significantly. Stitching was often crude and inconsistent.

The very first baseballs used in the 1840s had a “lemon peel” stitch pattern, a design with four sections stitched together using exterior seam welds, quite different from the figure-eight pattern we’re accustomed to today.

The size of lemon peel balls were small when compared to today’s baseball.

1857 – Adoption of Rubber Core

Prior to 1857, baseballs were typically filled with cork or rubber-like materials. However, in this year, the NABBP officially adopted the rubber core, which provided greater consistency and durability to the ball.

1861 to 1865 – US Civil War Begins

The American Civil War starts on April 12, 1861 and ends on May 26, 1865

1872 – The First Baseball Specifications

In 1872, the National Association of Base Ball Players (NABBP) established the first formal baseball specifications.

The ball was required to have a circumference between 9 and 9.25 inches, weigh between 5.5 and 6 ounces, and each ball should be stitched with 108 double stitches.

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Baseball Manufacturers (1900s)

In 1909, the Spalding Company became the first official baseball manufacturer for Major League Baseball (MLB). This marked the beginning of a long-standing partnership between MLB and Spalding.

Early 1900s is also marked by the “Dead Ball” era, creating boredom and malcontent among players and fans.

1900s – Beginning of the Dead Ball Era

By the dawn of the 20th century, the handmade era began to fade as factories started to produce baseballs.

This period, known as the “Dead Ball Era” which lasted until 1920, saw balls made with a rubber core wrapped in yarn and encased in a leather cover.

The balls were softer and less tightly wound, which resulted in fewer home runs.

1901 – Formation of The American League

Originally known as the Western League (1995-1889), the American League was formed on January 28, 1901. The original eight teams in the league were:

  • Boston Americans (Boston Red Sox)
  • Chicago White Stockings (Chicago White Sox)
  • Cleveland Bluebirds (Cleveland Guardians)
  • Detroit Tigers
  • Baltimore Orioles
  • Philadelphia Athletics (Oakland Athletics)
  • Milwaukee Brewers
  • Washing Senators (Minnesota Twins)

1903 – The National Agreement

The National League (formed in 1876) and the American League (formed in 1901) cemented their cooperation with the National Agreement in 1903.

The agreement set the stage for an annual championship series (now known as the MLB World Series) between the champions of both leagues. The agreement also solidified the structure and legitimacy of professional baseball in the United States, laying the foundation for the modern era of the sport.

1909 – First Official Baseball Manufacturer

In 1909, the Spalding Company became the first official baseball manufacturer for Major League Baseball (MLB). This marked the beginning of a long-standing partnership between MLB and Spalding.

1910 – Introduction to Cork Center

In 1910, a crucial change was made to the baseball’s design when the Spalding Company introduced a cork center in place of rubber.

The cork was lighter and allowed for a tighter wind of the yarn, resulting in a firmer ball. This adjustment ultimately led to more “lively” balls.

1914 – Start of the World War 1

World War I (the First World War) begins on July 28, 1914 and ends on November 11, 1918

1920 – The Introduction of the Livelier Ball

In response to a decline in offensive production, the National League made changes to the baseball’s composition, resulting in a livelier ball in 1920.

The cork core was replaced with a cushioned cork center, making the ball more resilient and increasing offensive numbers.

1933 – Modern baseball standard implemented by the American league

The American League settled on a new ball manufacturing specifications that closely resembles the specification used to make modern baseballs.

The specifications of the ball called for a double cushioned cork center (weighing 7/8 ounces), 71 yards of blue gray woolen yarn to build up the core to 7 3/4 inches in circumference, weighing 3 /18 ounces.

Next layer was formed by wrapping 41 yards of white woolen yarn to increase the circumference to 8 1/4 inches with the weigh increasing to 3 7/8 ounces.

A coat of special rubber cement is then applied, followed by 41 yards of blue-gray woolen, and the final 100 yards of 20/2 ply fine cotton, establishing 8 7/8 inches in circumference and a weight of 4 3/8 ounces.

Finally, another coat of rubber cement is applied to which an alum tanned horsehide weighing an 1/2 ounce and 5/100 thick leather covers are sewn with a double stitch of four-strand read thread.

The finished ball is 9 to 9 1/8 inches in circumference, and weigh 5 to 5 1/8 ounces.

Up until this time, this “baseball making recipe” was jealously guarded by the manufacturers.

1934 – Agreement on a Uniform Livelier Ball

On January 6, 1934, the National League and the American league agreed to use a standardized baseball that was used in the American League in 1933.

The new standard ball is a medium between the “jackrabbit” of the American League and the slower, “reaction” ball of the National League, offering more lively ball than earlier baseballs, aimed at increasing offense and fan excitement in the National League.

1938 – Federal Scientists to test baseballs

The president of the Senators (currently known as the Minnesota Twins) announced that he will ask the Bureau of Standards (now known as the NIST or National Institute of Standards and Technology) to test the National League’s “dead ball” and the American League’s “rabbit ball”.

1939 – Start of the World War 2

World War II (the Second World War) begins on September 1, 1939 and ends on September 2, 1945.

1942 – Re-purposing golf pills into baseballs

The War Production Board (WPB) reports that 720,000 baseballs of quality “equal to pre-war cork-centered baseballs” would be made by use of leftover insides of golf balls. These baseballs are intended for college, high-school and local leagues as the bid leagues are believed to have enough leftover baseball from the 1942 season.

Fun Fact
Did you know that in 1942, each of the sixteen major league clubs used approximately 1,600 dozen baseballs per season?

1943 – Putting “jack rabbit” back into the standard baseball

Due to World War 2, previously used materials to construct baseballs was severely limited. The revised baseballs caused hitting to slump dramatically and players complained the ball had been deadened.

So a three-man committee voted to adopt the 1939 “jack rabbit” ball standards in March for the 1943 season.

The revised ball specification calls for the granulated cork center, surrounded by two layers of balata rubber. This center will not be as lively as the one used when top grade cork and rubber were available. To compensate, manufacturers will increase the resiliency by changing the method of winding the yarn and use a different cover.

Livelier Baseballs (1950s)

1953 – Cooper Union alleges “Jackrabbit” ball

According to Cooper Union, an institution specializing in scientific studies, alleges that the baseballs used in the major leagues in 1953 on average, could travel eight percent more than the previous year. That meant an an regular 300 foot flyball in 1952 may turn into 324-foot home run in 1953.

AG Spalding, which made baseballs for both the American and National Leagues, responded that the age of 1952 baseballs may have skewed the results.

In 1953, baseballs averaged 143.7 grams to 147 grams.

Fun Fact
When questioned about a “lively ball” during a 1957 interview, an AG Spalding representative claimed that there has been no changes made to the ball since he joined the firm in 1919!

When reminded that he is under oath, the official mentioned the First, Fourth, Fifth, and Fourteenth Amendments!

Korean War, which began on June 25, 1950, ends on July 27, 1953.

1955 – Start of the Vietnam War

The Vietnam War begins on November 1, 1954 and ends on April 30, 1975.

1969 – Controversy over “distinctly livelier” ball

The MLB ball standard is for it to have a circumference between 9 and 9 1/4 inches and weigh between 5 and 5 1/4 ounces.

The 1969 season ends with 3,119 total home runs, which is 56% increase from the previous year, which cause fans and players allege that the 1969 baseball is livelier than the one used in recent past.

However, it should be noted that:

  • each league added two new teams (total of four new teams)
  • rule changes adopted to counteract the dominance of pitching (mound was lowered and strike zone enlarged)

Factoring these changes, MLB saw 36% increase in home runs compared to previous year.


The fifth Major League Baseball commissioner Bowie Kuhn tells the press that he will thorough study the baseball’s resiliency by creating a new testing method and implement new standards next year.

1970 season ends with even higher number of home runs (3,429), however, probably due to the league using leftover stock.

1971 season ends with 2,863 home runs.

1974 – Cushioned Cork Center

In 1974, MLB introduced a revised “cushioned cork center” ball. The ball featured a cushioned cork core surrounded by rubber, resulting in increased bounciness and greater offense. This change led to a surge in home runs during that era.

1976 – Rawlings becomes the official supplier of baseballs to MLB

After several decades of minor changes, In 1976, Rawlings Sporting Goods became the official supplier of baseballs to MLB. The balls manufactured by Rawlings had to meet specific standards set by MLB, ensuring uniformity in weight, size, and performance.

The baseballs now featured a cushioned cork center, wound with nearly a mile of wool and poly/cotton yarn, and covered with premium cowhide leather, stitched together with precisely 108 double stitches.

1977 – Season ends with a massive 3,644 home runs

The American league adds Seattle Mariners and Toronto Blue Jays, increasing the total number of teams to 14 while the National League remains the same at 12 teams.

Rawlings replaces Spalding as the official supplier of baseballs to MLB.

1987 – Season ends with another record: 4,458 home

Fans allege another round of “juiced” balls but many sportswriters defend the home record as a byproduct of better athletes becoming hitters (rather than pitchers).

If the ball was not juiced, how come the 1988 season ended up with “only” 3,180 home runs which is more aligned with previous five years and next five years?

Standardized Baseballs (2000s)

2000 – Using a Single Standard Baseball

Previously, the American League and the National League remained as separate entities. During this time, America League balls came with red and blue stitching while the National League balls featured red and black stitching.

In 2000, both leagues legally merged into a single organization led by the Commissioner of Baseball and agreed to use identical baseballs that came with red stitches to maintain consistency.

Some players also stated that they were able to see the ball better due to the use of red stitches.

2010 – “Juiced Ball” Controversy

Many players, analysts, and fans noticed a significant surge in home runs during this period, leading to speculation that the ball’s construction or composition had been modified.

While the exact cause of the offensive surge remained a topic of debate, investigations and studies suggested that changes in manufacturing processes and the use of different materials may have contributed to the increased power numbers.

The “juiced ball” controversy sparked discussions about the balance between offense and pitching, and MLB made efforts to address the issue by conducting studies and making adjustments to ball specifications in subsequent years.

2017 – Home Run spike raises questions

The 2017 season ends with 6,105 home runs

2019 – “Juiced Ball” Controversy # 2

Similar to the previous controversy, this debate centered around allegations that baseballs were intentionally altered to favor hitters, resulting in an increased number of home runs and higher offensive statistics where players and analysts agreed that there was unprecedented surge in power numbers.

Again, the controversy sparked discussions about the game’s integrity and the delicate balance between offense and pitching.

MLB commissioned independent studies to examine the issue, but found no definitive evidence of intentional alteration. MLB continued to monitor ball specifications and made adjustments in subsequent seasons to address the concerns surrounding the “juiced ball” phenomenon.


Today’s modern baseball represents the culmination of a rich history of innovation and refinement. Through careful craftsmanship and technological advances, baseballs have evolved to meet the demands of the game.

From standardized specifications to enhanced performance, the modern ball embodies the delicate balance between offense and defense, providing a level playing field for players to showcase their skills.

While controversies surrounding ball composition and its impact on the game persist, the ongoing pursuit of excellence and fair play ensures that the ball continues to be the iconic symbol of timeless tradition and excitement of baseball.

Please don’t forget to visit Buying Baseballs – Reference Articles page to read other fascinating information about baseballs!

Ian Marshall

Sunday 24th of March 2024

thanks im using this for my school assignment

Baseball Dad

Thursday 28th of March 2024

Hi Ian,

Awesome! Have fun with your school project!